Bruce -
The fill gauge, at least should be easy to fix. It can be easily removed from the body of the toilet. Once you have removed it, make sure that the float is not bound up with debris - if it is, simply rinse it off and put it back.
If this is not the problem, then one of the float rods is probably bent a bit. The float rides up and down on two metal rods, and it must ride smoothly. If one of the rods is bent a bit, the float will bind. Try to move the float up and down with your finger - does it move smoothly? If not, note where it binds, and bend the rod back into shape until it does move smoothly.
It is possible, though much less likely, that the center strip - a flat metal strip with a twist in it - is bent. Again, if this is the case, just tweak it back into the correct shape.
The leak at the floor valve is a bit more annoying to work with, because you have to get down on your hands and knees, and the bathroom doesn't have a lot of space to work in. Most likely, the mounting bolts/clips simply need to be tightened, to reassert the seal at the Slide-EZ valve. At worst, you will need to release the clips and lift the toilet off the floor to see what is going on.
You can see good pictures of all this on the Thetford web site. For pix of the gauge:
http://www.thetford.com/parts_electramagic.cfm
For pics of the mounting bolts and clips, seals, and valves, plus installation/removal instructions:
http://www.thetford.com/permanent_el...gicservice.cfm
I have to agree with you that some of the "gentle" deodorants don't work. We haven't tried Odorlos, but tried one called Enviro-Chem, and it was terrible. Like you, I threw it out.
I have to disagree with you that the toilet is marginal. We use ours full time for everything, and it has been great. You do have to follow Thetford's instructions, though. If you use an improper deodorant, or try to save a few cents by using too little - well, you can't blame the toilet if it smells. I haven't tried any of the tabs, pucks, or powders, and don't intend to. Use a full 8 ounce bottle of Aqua-Kem, and it works fine. Don't get hung up on formaldehyde - that is advertising hype from makers of non-formaldehyde liquids. (You can do a search on "formaldehyde" and find a couple long threads on the topic.)
And finally, if you have a very sensitive nose, there have been a couple rather ingenious forced-ventiation projects described on this forum. The Search tool will uncover those as well.
Bill