I'd say put the fish in bags. No need to keep much water in the tank, just make sure to keep the gravel and filter medium wet. It'll be heavy enough just with that. If possible, keep as much of the seasoned tank water as you can (but transporting that will be tough). With an active biological filter maintained, and the reduced bio-load from the removed fish, the tank should be fine. To be on the safe side, you could add a lot of fast-growing stem plants to the tank once you get it refilled in its new location. They'll really help to keep ammonia spikes down by sucking up the un-bio-filtered fish wastes. The bio-filter should come back quickly with this method. And, if you don't want the tank planted in the long-term, just slowly remove the stem plants over the next few weeks. The filter should keep up. Just add any fish as slowly as you can. That's my .02