I'm going to assume that your '98 HR Endeavor has the Duo-Therm 4 button comfort control center. These have become quite problematic as they age. Mine, thankfully, has only required intermittent cleaning of the contacts to keep it working. You can view or download a copy of the service manual and trouble shooting guide from
Bryant RV by clicking on the link. The first couple of times mine acted up I picked up some electrical contact cleaner from Radio Shack, removed the thermostat from the wall and it's plastic case and hit the switches with a couple of blasts of spray cleaner. The last time it needed cleaning I disassembled the switches and gave them a good cleaning... and it's still working fine. The manual will give you a great overview of the thermostats operation and I'm sure you will be able to figure out how to find/display your 'Zone 2' settings.
If you have the 5 button thermostat that manual is available
Here but it's not as complete as the 4 button version.
You didn't mention what type/model of toilet you have... but replacement of the seal is usually pretty straight forward and parts are generally available online or from CW. I picked up my last set of seals on ebay and saved quite a bit. Do a bit of searching online and you'll probably find 'How to' information and maybe even a video or two. The last seal replacement I did took about an hour but that included a dumping and rinsing the tank and a complete cleaning of the toilet. A 'Yucky' job to be sure but it's doable.
On Edit: If you have a Sealand toilet, HR used them for a number of years, you can find a manual
Here and a 'How to' video
Here