Per Chalkie's idea of a rear area. I wrote a campaign though never played where the PCs after making it to freindly lines were allowed to a recreation and relaxation area. An entire town had been converted to that purpose. Where they could eat, sleep in a real bed in one of the converted houses and hotels, eat at any number of restrains, sports fields, pools, theaters librarys and even a USO and post office to write letters and have them sent to the central collection point where one day they may be shipped home and delivered.
There was even a store where they could buy, sell and barter. And of course a black market.
There were however some rules. NO WEAPONS only officers and Senior Staff NCO's where allowed them. There were local police and MPs from every major force in the region.
I loved the idea since it would allow the PCs to do as Chalk said get into trouble but more in a good natured way.
That reminds me, why does the campaign have to be centered soley around combat? I know when we played T2K and D&D we always had some good natured fights in the taverns and bars and among other units and groups that was secondary to the main mission. We also did this several times while waiting for the fleet to take us home at Bremerhaven.
And then I have mentioned my idea of a Tavern or Roadhouse or Inn on this group, the old group and the yahoo one. A Inn of sorts in the wilderness that is left alone and considered a nuetral area by both sides, although it gets tense at times. But hey it must be nice to go to a bar, see a Russian and not have to worry about having him run you over with his tank. Besides its a high priority intelligence position used by both sides who don't want to loose it. <And a good deal of blackmarketeering as well>