Naively, I thought that my biggest hardship with cycling on dirt and gravel would be the technical aspect - dealing with roots, rocks, loose surfaces and the like. Well, ha-ha. While it's not exactly a surprise that cycling on rough terrain takes more effort than on a smooth road (think walking on sand vs on a paved sidewalk), I did not expect it to be quite this draining. Replacing only 5 miles of a 40 mile ride with off-road trails made a big difference in how tired I felt afterwards. And here I thought that I was getting fit with all that roadcycling; turns out I am a weakling.
Molehills become mountains
Directly related to the previous point, is the need to use lower gearing for everything. Benign-looking upward inclines on gravel or packed sand feel like proper hills do on pavement. Huge difference!
This simple concept has been tremendously helpful. If a stretch of the trail seems difficult, or slippery, or overly bumpy, continuing to pedal (instead of coasting or trying to stop) is the best way to get through it. It was counter-intuitive in the beginning, but quickly became intuitive. The best way not to fall or get stuck is to quickly switch to a low enough gear and pedal through it.
Foot retention is helpful
Having my feet snugly inside Power Grips helps when I get nervous, discouraging me from attempting to stop the bike (which is a good way to fall) and teaching me how to keep my balance.
Beautiful surroundings are a huge motivator for me. The first couple of trails I tried were sort of monotonously woodsy and led nowhere. I did not find cycling on them particularly enjoyable, because all the focus was on the terrain and there wasn't anything exciting to look at. Then we went through a different set of trails - with farms, meadows, varied stretches of woods, historical structures, fields of sunflowers, and a network of narrower paths going off in all directions - and it became an entirely different story. Suddenly I was interested and wanted to keep going despite being tired, and suddenly that narrow muddy offshoot of the path began to seem worth following just to see where it would lead. After a couple of these experiences, I will amend my earlier ambivalent comments about cycling off road with "I like it, if the scenery is worth it."
It surprised me to learn how many options there are for cycling off road close to Boston. The trails are all fairly short, but there is a great deal of variety. Though I am starting to doubt whether I am fit enough for even the easy 40 mile D2R2 route, I am enjoying this cautious exploration of a new type of cycling. It was not love at first site, but it is growing on me - particularly if meadows and old farms are involved.