AlexJet
Explorer
Odysseys are nice. They are just about the only ones who make a thin plate cranking battery that is also rated for deep cycle use.
Note in the specs on the PC1500 that it can handle 400 cycles to 80% discharge. That's the lifecycle. That means you can drain it 80% 400 times and then you'll probably have to replace it. All lead-acid batteries are like that. The deeper you go, the less cycles you'll get. That same battery could probably do 3000 cycles if you only drained it 25%. You'd probably get 10,000 cycles if you only drained it 5% or less for engine starting.
If you intend to run auxiliary loads with the engine off, then you should go with a standard aux battery setup - use an isolator to charge the second battery when the engine is running, and isolate the batteries when the engine is not running. Then attach your aux loads to the aux battery so you don't drain your engine battery while running those aux loads.
For a winch, I would hook the winch up to the engine battery to supply heavy amps under load, and allow the aux battery to help out as needed. The engine will probably be running in that situation so the alternator will help out as well. (Well...I would with normal batteries. With Odysseys, it probably doesn't matter which battery you hook the winch up to as long as the battery cables between them are heavy enough to handle the amps.)
All other aux loads should go to the aux battery.
If you hook up your aux loads to the engine battery and run it down, then the aux battery is basically useless except to maybe jump start the truck when you need to, and to help out when running the winch.
As far as charging, the only difference in those batteries you listed is the capacity. They all accept exactly the same charge parameters. The charging specs are described in the Odyssey Tech Manual:
http://www.odysseybatteries.com/files/US-ODY-TM-001_0411_000.pdf
In other words, with those Odysseys, being charged from a vehicle's charging system, you can mix and match them to your heart's content.
Also, keep in mind that even 68 amp*hours is not a hell of a lot when talking about running aux loads for days while camping. If you want a lot of cycles (long life) from those expensive batteries, then don't drain them below 50% - which means that you'd actually have 34ah available.
Thanks for your comments. Very helpful notes. I'm not using much power when the engine is off. It may be just running the radio (I don't have subwoofers or amplifiers, just basic radio) and couple lights to light up the camping sites (want to replace my halogen fogs with LEDs, so they can drain less).