We have just been talking on the forum about how we all seem to do better when we go on vacation than when we are at home. Just getting out and having nothing to do but have fun seems to make things a lot better. So I wouldn't put off having vacations, even if the local dates have to slow down. It's like getting away from house chores, work, annoying associates, etc. just makes the guts relax and function more normally; getting out just for a night doesn't seem to do as well since you tend to still dwell on all of that stuff.
I feel uncomfortable at movie theaters between having to crawl over people and then having to miss part of the movie by going to the bathroom. Same thing goes for sporting events, where you have all of that, plus long lines at the bathroom. However, there are many actitivies that you can do that don't involve food and which can be done without too much problem:
Historic sites are fun (at least to me, Miss History Major, lol) and National Historic Sites of any size always have bathrooms--provided you are there during their regular operating hours.
National Parks are nice too, but the bathrooms can be further away than at historic sites, where everything tends to be grouped together. Also, be especially mindful of the "on" season. When my parents and I got on the Blue Ridge Parkway in early April some years ago we found they still had ALL of their rest areas closed for the off-season. We ended up peeing out in the woods at one point, lol. Definitely not a good place for someone with D to be.
Toliet paper and an extra pair of underwear is never a bad thing to have in the car.
Minature Golf is fun and always has a bathroom nearby, although you may have to walk back through the other greens to get to it.
Bowling is a good activity since you can play your game at your leisure (so long as you're not there on League night!) and it has indoor toliets.
My fiance and I have had some fairly intense games of Monopoly and Risk and have played all sorts of card games. These can be fun and regularly scheduled and can invovle home-cooked food or none at all. If you have the ability to pool two computers together, you can play games on them and match each other or team up on them. My fiance and I do this sometimes with one of our medieval war games.
When Stuart and I took our vacation last year, we only ate one meal out a day--supper. We packed our own lunch and breakfast and this went a long ways towards helping out my poor guts. Fast food is rarely easy on you, and even restaurant food can be too fatty/greasy/fried/junkie to be good for you either. If there are things he knows he can eat with relative safety, then you should try packing meals when you go out. This is a lot cheaper too!
Stuart and I also do medieval reenacting together. I don't have a problem doing this because we almost always feed ourselves breakfast and lunch and supper, while usually a huge feast, is home-cooked and therefore has less fat, grease and sugar than meals out. And I'm with a great bunch of people, some of whom also have stomach problems, so I'm not embarrassed if, during the course of the day, I have to go to the toliet several times or abstain from food. We camp with a group of friends every year for a week down in MS at a big event and communal dinner can get interesting with all the people who can't eat this, that or the other because of reactions or allergies. Sometimes we even sit around and compare ailments! So it might be that you guys, if you have a common interest, can join some sort of hobby organization which won't be hard on his guts and can be something that you share together. I find my time reenacting for a weekend is a lot like a mini-vacation and my guts tend to behave better, not worse.
Lil's got a good list of no-nos for you. I would add that sugar alcohols are found in sugar-free and low-sugar products, so be on the lookout for those things. They absolutely KILL me! Tomatoes can bother some people, especially in large quantities, because they are acidic. Orange juice and lemons can be a bother too, for the same reason. Coffee is out because caffeine is generally bad for you and because it's acidic. This goes for non-caffieneted drinks as well. The carbonation in them can be espeically problematic for people with bloating. My main offenders are deep-fried things (I can handle homemade, skillet fried stuff, though), apples and apple juice, gravy and caffeine. I seem to be better off than most because I can handle milk, tomatoes and other things, although I have to be a bit moderate with the orange juice; no more than one glass a day. Oh, and alcohol, especially beers, seems to be bad for most everyone--although a few people have found that hard liquor can actually help calm their guts down. It will only take a drink or two to realize, the next day, which category you fall into.
Now might be a good time to get into sports, lol. Stuart and I like to sit around in the fall and listen to the Tennessee football games. If we had cable, we'd watch it, but such as it is, we listen on the radio. We tend to converse between plays and that's fun to do together even if we're not really "doing" anything in particular. After being with someone for a while, going and doing isn't as important as just being together and talking. I like an hour or two in bed reviewing the monarchies of England and discoursing on the lives of the average Medieval peasant better than I like going out and doing a lot of things! It helps, of course, that Stuart and I happen to be, generally speaking, lazy homebodies by nature, lol.