So you have a trail book, confused? Here are a few clarifications
Easy
Easy means you can do it. No special skills or equipment required. Often this means the the trail is wide, clearly marked and passable by many means (often including wheel chair) It does not mean flat, short, or without effort but in general they are not too long (generally under 5 km) and the elevation gain will be gradual. It means passable by just about anyone. Usually well maintained and close to civilization. Check the distance and the elevation gain and that will tell you a lot more about how this will feel.
Moderate
This means you are going up. Other possible meanings are steeper sections, rockier terrain or roots. This also usually means they are a bit longer, think 6-15km. Still completely doable. Check the distance and take your time. These hikes are usually where the fun starts! More interesting terrain, better payoffs and when you start going up in difficulty and less people :) And thats a plus. Here you will still find well marked paths and no technical skill.
Moderately Difficult
Longer. Higher. Steeper. This is where you will start to see the elevation gain more concentrated but still not climbing. The paths will still be well marked but not as wide and often include roots or rocks to walk on. The distances will be above 10km. For these walks read some reviews as this is a broad category.
Difficult
High, long, steep. In some places the path may disappear. Some technical skill will likely be required. Do your research and dont attempt this until you are quite confident you can handle it. There is lots of challenge in the moderately difficult category to keep you busy :)
Elevation Gain
This is a misleading term. This is a measurement from the start point to the highest point on the trail. Why its deceptive is that could be all in one go, or be flat and steep sections, or could go up and down and up and down (meaning you will climb more than this height but not stand higher than the gain)
So could be gradual, steep, up down, or varied. Read some reviews as often they will say things like "steady ascent" or "long flat section with steep climb at the end"
*all that being said there are particular ratings to express steepness that may be listed if you are climbing in the mountains.
they are as follows: (as per http://outdoorswithdave.com/climbing/climbing-ratings)
Class 1: Walking, on an established trail.
Class 2: Hiking, up a steep incline, possibly using your hands for balance.
Class 3: Climbing up a steep hillside; a rope is not normally used.
Class 4: Exposed climbing, following a ledge system for example. A rope would be used to belay past places where a fall could be lethal.
Class 5: This is where technical rock climbing begins. A 3 point stance (Two hands and a foot or two feet and a hand) is needed. A rope and protection are needed to safeguard a fall by the person leading. Any unprotected fall from a class 5 climb would be harmful if not fatal. Class 5 climbs are subdivided into categories to give more detail.
Logging Road
This means that the path is wide enough to accommodate a truck going down it. Now that is smaller than you may thing but really this can range from a gravel road to something that looks more like a double wide path. The book will say whether this is a commonly used road or just an access road for rangers and supplies. Usually they are not the most scenic parts of the route but don't be scared off, they can still offer some stunning views and I have yet to be on a trail that is all logging road.
*the one thing to consider is often these trails are more popular for bikers and sometimes horses.
Seasonal
This most likely means closed in the winter. Often you could still go on the path if you like but know that it is not maintained off season so it will not be clear.
And if there are outhouses they are not open in the winter.
*there is almost always more snow at higher elevations so don't let a lack of snow at the base deceive you. You could run into very different conditions on the trail.
Easy means you can do it. No special skills or equipment required. Often this means the the trail is wide, clearly marked and passable by many means (often including wheel chair) It does not mean flat, short, or without effort but in general they are not too long (generally under 5 km) and the elevation gain will be gradual. It means passable by just about anyone. Usually well maintained and close to civilization. Check the distance and the elevation gain and that will tell you a lot more about how this will feel.
Moderate
This means you are going up. Other possible meanings are steeper sections, rockier terrain or roots. This also usually means they are a bit longer, think 6-15km. Still completely doable. Check the distance and take your time. These hikes are usually where the fun starts! More interesting terrain, better payoffs and when you start going up in difficulty and less people :) And thats a plus. Here you will still find well marked paths and no technical skill.
Moderately Difficult
Longer. Higher. Steeper. This is where you will start to see the elevation gain more concentrated but still not climbing. The paths will still be well marked but not as wide and often include roots or rocks to walk on. The distances will be above 10km. For these walks read some reviews as this is a broad category.
Difficult
High, long, steep. In some places the path may disappear. Some technical skill will likely be required. Do your research and dont attempt this until you are quite confident you can handle it. There is lots of challenge in the moderately difficult category to keep you busy :)
Elevation Gain
This is a misleading term. This is a measurement from the start point to the highest point on the trail. Why its deceptive is that could be all in one go, or be flat and steep sections, or could go up and down and up and down (meaning you will climb more than this height but not stand higher than the gain)
So could be gradual, steep, up down, or varied. Read some reviews as often they will say things like "steady ascent" or "long flat section with steep climb at the end"
*all that being said there are particular ratings to express steepness that may be listed if you are climbing in the mountains.
they are as follows: (as per http://outdoorswithdave.com/climbing/climbing-ratings)
Class 1: Walking, on an established trail.
Class 2: Hiking, up a steep incline, possibly using your hands for balance.
Class 3: Climbing up a steep hillside; a rope is not normally used.
Class 4: Exposed climbing, following a ledge system for example. A rope would be used to belay past places where a fall could be lethal.
Class 5: This is where technical rock climbing begins. A 3 point stance (Two hands and a foot or two feet and a hand) is needed. A rope and protection are needed to safeguard a fall by the person leading. Any unprotected fall from a class 5 climb would be harmful if not fatal. Class 5 climbs are subdivided into categories to give more detail.
Logging Road
This means that the path is wide enough to accommodate a truck going down it. Now that is smaller than you may thing but really this can range from a gravel road to something that looks more like a double wide path. The book will say whether this is a commonly used road or just an access road for rangers and supplies. Usually they are not the most scenic parts of the route but don't be scared off, they can still offer some stunning views and I have yet to be on a trail that is all logging road.
*the one thing to consider is often these trails are more popular for bikers and sometimes horses.
Seasonal
This most likely means closed in the winter. Often you could still go on the path if you like but know that it is not maintained off season so it will not be clear.
And if there are outhouses they are not open in the winter.
*there is almost always more snow at higher elevations so don't let a lack of snow at the base deceive you. You could run into very different conditions on the trail.