I have tried several different tacks. I am not a runner. I use weights, cycle and elliptical at home. I always pack workout clothes. If I have to stay in a hotel I look for a one with a gym or at least an exercise room. A pool would be nice. Some facilities are quite good, others minimal or not in good condition. Best I've been in, Dallas Crowne Plaza, had a full weight room, several aerobics machines and a nice pool. All in excellent condition. The worst advertised a gym room and had a clapped out Universal machine with not much else. Driving, I used to pack a couple of 1" dumbbell handles and about 30# of plates. They fit in a small molded plastic, flat equipment case. That got old. I discovered exercise tubing. Tubing is available in different tension ratings. I got mine at Walmart. Everlast has a $20 kit of three tubes and two handles so tubes can be doubled or tripled to vary tensions. A short tube and a long tube and a jump rope will allow you to just about simulate a normal gym workout with a couple if ounces of equipment and next to no luggage space. Compensate for lack of weight with high reps. Add some bodyweight exercises, pushups, crunches, squats, sissy squats, and stretches. You can do 45 minutes in your room or wherever. Great for a cold, rainy day when you might not want to run. There are tubing workouts online. Use a hassock for a bench if available. In hotels, at least spread a guest towel on the floor. Run stairs for aerobics and warm-up.