You will get more hours from a pair of six volt batteries for house batteries (such as Trojan 105's), if that matter to you or do dry camping. Else the marine group 31 for house will work and be maintenance free.
The group 27 marine battery for the chassis batty is good if you have electric slides, else a starting only battery is fine.
I use and recommend Wal-Mart auto/marine batteries - priced well, well rated, good warranty, serviced at Wal-Mart's everywhere.
Vince and Susan
2011 Tiffin Phaeton 40QTH (Cummins ISC/Freightliner)
Flat towing a modified 2005 Jeep (Rubicon Wrangler)
Previously a 2002 Fleetwood Pace Arrow 37A and a 1995 Safari Trek 2830.