For intra-team communications FRS or MURS would be a low cost option, but you would have some limitations on equipment choices and their ability to withstand working in "disaster mode". You might want to contact a real frequency coordinator to see about licensing a nation-wide frequency, even if it was on a "secondary basis". That way you would be able to choose a broader line of radios and have better frequency protection.
As to the 50 mile communication requirement, I'm going to assume that your envisioning a NIMS style base camp configuration and I would reccomend low band (50 MHz) for this communications. It would be fixed at both ends with the distant communicator being responsible for being the relay from the distant team back to base camp. It would require a bit more set-up but I think that the lower cost and reduced chance of congestion that you could see with satellite is also a good choice.
Also there are many websites that could assist you, with one of them being the DHS SAFECOM website.
SAFECOM
Good luck.
Mark