Hi Paul,
Getting it out isn't that bad. You'll see that, at the base of the battery, between the battery and the bumper, you have a bolt going through a small plate holding the battery in place. Sort of hard to explain, but if you look around you'll find it. Remove that bolt and the battery is free to slide out sideways.
As far as the electrical connection goes, disconnecting the negative is fairly easy. The cable goes to the chassis ground and at the battery end, you can see it quite well. Once that is disconnected, I cover the negative battery terminal with a blanket to avoid shorting it with the positive terminal. The negative terminal has to remain floating if you want to be safe during the process.
I used a mirror to see how the positive side was connected. I then used a small ratchet to disconnect the positive terminal. I put electrical tape on the ratchet's handle to make doubly sure I didn't short anything. This is certainly overkill, because if the negative terminal is floating, it should be safe.
You can then move back and slide the battery out.
To get a larger group 27 (105 Ah) battery in there was a bit more of a challenge. I removed the bolt holding the propane connector to the rear bumper to give me a bit more room. The battery was too heavy to hold at arm's length. I used a floor jack with a 2 foot by 2 foot piece of plywood on top of it. I placed the new battery in th middle of the piece of plywood. As my wife was raising the jack, I held the side of the plywood to keep everything in balance. When it was fully raised, the plywood was in contact with the rear bumper and the generator and propane tank. The battery just needed to be raised by hand another half inch or so and then slid into place. I thought the new larger battery was sticking out a bit too much so I made a bracket out of angle iron to support it.
Later on I added an inverter. Making the connections by feel really isn't fun!
Bill