I've read some of the posts how others are hooking up deep cycle 
batteries, but does anyone just use a 2nd normal cranking-type 
battery to run stuff?  

I know in the sailboats we've chartered, they ususally have 2
cranking batteries with a switch that controls flow to and from the
batteries with the following options:

1 - 2 - both - none

When running the diesel or on shore power, we set the switch to
"both" to keep a charge on both.  When running lights and
instruments with the diesel off (preferred mode, of course :-), we
use battery 1 on odd-numbered dates and battery 2 on even-numbered
dates.  When going ashore, we set the switch to "none" to avoid 
anything bleeding the system with anything we accidentally left on.

Comments on this setup?

-Karl
Karl F. Bloss - blosskf@ttown.apci.com
'87 Vanagon GL  "Beverley"