Replace Travis with a cardboard cut out...no one would notice for a few episodes.
Other ways to save money:
Have Trip stuck in on a shuttlepod or soundstage "planet" with a guest star every other week. Like they did in season 2.
Have all the guest parts actually played by the series regulars. They did that on DS9 for like a whole season's worth of episodes.
Recap everything noteworthy that happened in the entires series before the opening of each episode. That should shave off 1 or 2 minutes
Changing the opening credits cop-show style, with exciting montages from older episodes that promise a lot but deliver nothing since the reduced budget prohibits much action. (Much like most cop/detective shows were.)