I changed out the 12 volt on my gas Adventurer to 6 volt and have been very pleased. The Trojan is an excellent choice, however, I was close to a Camping Word when mine died so I went with the Interstate 6 volt whicj has similar specs to the Trojan. Most golf carts us Trojan battteries so that is why they are so popular and reliable.
One note, the 6 volt is taller so your holddown rod will be too short. The fix is simple. Go to a hardware store and bu coupling nuts, which are simply nuts that are about 1/2 inch long. Get the right size to fit your exsisting rod and mesure how much more rod you need and either bu a bolt the correct length or by a length of threaed rod and cut it to fit. Avery simple fix. Also, the 6 volt Interstate Battteries have a quick release cap cover that lets you remove and replace the caps in one quick snap. Makes checking the water a breeze.
One last note, the 6-volt batteries did not ahve a carry strap so you need a way to lower then into your coach tray. I ahd a piece of velcro about 3 feet long that was the same width as the slots on the side of the battery so i put it through, locked the velcor onto itself and set them in and the remove the velcro. Lacking that you can us your belt if it is narrow enought to fit through the slots.
Good Luck. We get about 3 times the reserve on these that we got on the 12 volt ones.
2001 Winnebago 37G, 2003 Saturn L300, brakebuddy Laissez les bon temps roulez