I travel a lot for my job - I'm generally away three weeks a month. Managing a healthy eating plan while travelling can be a nightmare, so here's how I've adapted it:
1) Intermittent Fasting - e.g. LeanGains. Finding Martin's site was a revolution for me. Learning that it didn't really matter when I ate saved me from the bodybuilding and dieting mantra (aka bullshit) of "stoking the metabolic fire" by eating every three hours. It's made my life easier and more satisfying. I get far more pleasure from a big evening meal than six snacks through the day. In addition, while travelling, it helps me focus on what's important - the quality of the food I'm eating. By only eating in the evening after work, I can make sure that I'm in a restaurant, hotel or supermarket and making decent food choices. Side benefits are that I can work through lunch (since I don't eat lunch) and this has sometimes enabled me to finish earlier, or gives me the extra time I sometimes need to finish a job.
2) Hyperlipid / low carb / paleo - A typical meal (one I'm eating as I write this!) is something like this:
Chicken Caesar Salad
Cheeseburger (no bun, no fries)
Cheese platter (no biscuits / crackers)
Glass of red wine
Protein shake for dessert - 1 pint whole milk, 150ml single cream, 2 scoops of your preferred whey protein.
I've no idea of the macros, but it's probably something like 50g carbs, 100g protein, 50g fat. The main thing is that it's tasty, filling and keeps me going until 24 hours later.
This is more protein than Peter @ Hyperlipid would go for, but he's not into weightlifting. At a bodyweight of 59kg (currently), I deadlift ~120kg for 10 reps, do 40kg weighted dips for 10 reps and 20kg+ weighted chinups for 10 reps. I figure I need the protein.
3) Exercise - being in a hotel for four nights of the week is not especially fun, so I always try and book one with a gym. My workouts when away are much less serious and these days I just use them as an excuse to burn some glycogen, use up some time and "earn" my dinner. When I'm home, my workouts will be much more structured and emphasise making progress - i.e. "progressive overload". I try to put more weight on the bar / dumbbell each time.