A few questions... are you going to be dry-camping (no electric hookup) or staying at CG's that have shore power? Does your TT have a battery charge controller in it?
If you are going to be staying at sites with electric, a regular 12VDC Marine/RV battery will do the trick. It will care for your Brake-away switch with no problems.
If you are planning on a lot of dry-camping, then you will want to opt for a quality deep cycle battery (Trojan, USBattery..) that has more Ah. The ultimate setup for dry-camping is (2) 6 volt batteries (like the Trojan T105).. just remember you need to charge them some how.
2013 Jayco Eagle 284BHS
250Watt Grape Solar Panel, MorningStar MPPT 60 Charge Controller
1500 Watt Ramsond PSI, 2 Trojan T145 Batteries (260Ah)
2 - AirSight Wireless IP Cameras (used as rear view cameras)
EnGenius WI-FI extender, D-Link wireless (n) modem
MagicJack Internet Phone
2012 Ford F150XLT, EcoBoost w/3.73
157" Wheel base, HD Towing Package
Our Solar Album http://www.jaycoowners.com/album.php?albumid=329