It's hard enough to find a bunch of people to play at a high levels of tennis even at home 100%. A lot of times you find these small circles of good players who will only play with each other or practice with their own team, but saying you played in college is like the secret password to get an invitation. Also the fact that you are young means you'll have no problem playing in one of the singles spots.
The hard part about a 75% travel schedule is the commitment. If you're away obviously you're not going to be in the lineup for that week, but if there's the possibility that you can be pulled away at the last minute, you need to make sure you have a sub ready to go otherwise you may not get scheduled if your captain can't count on you being there. Leagues here play 6pm on weeknights (and are strict about start times) and the main reason I don't play is because I can't guarantee I'll be able to get out of the office in time, you never know how traffic is going to be, if the courts are far away even under a best case scenario I may be cutting close on time.
As for playing tennis when you are on the road, keep in touch with your buddies from college and the guys you played with in juniors. Even if they can't play when you're in town, they may know of someone you can call. Network.