If flying, request a window seat in the emergency row or seat with extended legroom. Walk around the plane during the flight and stretch in the open sections. If traveling by automobile, plan a rest stop at least every 2 hours to stretch and walk around. Often hotels have agreements with health clubs that are within reach. If not, look in the phone book for a place to work out.
Most fitness centers have daily, weekly and monthly rates.
YMCA's are often good bets. Go for a swim - Jump in and swim some laps. Use the water to provide friendly resistance for different body parts. Surprisingly, you can get a good pump. Explore - Walk around the hallways and explore the hotel.