If you are willing to put your phone in a cradle and use bluetooth to talk, the Sleek is a great solution. Be sure you either purchase one made for your provider or the latest version that has a switch to go between Verizon and AT&T. Combined with a Wilson trucker antenna it does wonders.
As to a dual antenna system that boosts the signal from an outside antenna and retransmits it throughout your RV, the only ones currently available are 3G only, and in general you can only expect an amplified signal within 7' -10' of the inside antenna. There is a $900.00 system from Wilson that does both 3G &4G, but it requires more separation between antennas than you can get in a RV.
There are RV repeating systems on the horizon...
