You've been at this for 4 years now, just do what you have been doing...it seems to have worked well!
We go out of town every single weekend...well at least every Saturday. We usually get up super early and drive Lincoln and get home very late in the evening. We have been doing this for a couple years now, to care for my husbands elderly parents, (who refuse at this point to move into assisted living). It's very stressful, especially in the summer because they have a large lawn/yard that needs to be tended to plus grocery shopping, house work and laundry.
Even though we are rushed and stressed, I still managed to lose all my weight and keep it off going out of town every weekend. First, I always get up and eat a healthy breakfast at home...before we leave. No matter how early we leave I make sure I'm fed. I try to feed everyone, but that doesn't always happen...So when they stop at the bakery to pick up stuff for "grandma and grandpa" they usually load up for themselves. I get black coffee.
After we get chores done we take MIL/FIL out to lunch. They have a handful of places they like to eat, so I have researched them all and know what I can eat for 500 calories or under at each place.
For Supper I usually have a sandwich and some fruit and a yogurt I packed for myself, while everyone else orders pizza or something equally unhealthy and delicious. But sometimes I do have a piece or 2, OR maybe a "treat" at Dairy Queen. But the treats only started once I reached my ultimate weight goal of 140. Even when I hit my original goal of 158, I stayed away from most high calorie/low nutritional value food.
The thing is, I plan it out very carefully, my eating really depends on my weight. I also raised my weekend calories by 300 during the losing stage because It is harder at restaurants. But I was able to do it. Heck, this morning I weighed in at 139, so it totally can be done.