Lots of youtube vids available. If your lucky you might have a sticker with all the info. That is if you can read it. My sticker was right on top of axle(facing toward underneath of rv) and in middle of axle tube, but it was useless because it was marred up from road debris and dirt etc.
X 2 on above posts and once you pull hub you should be able to tell everything you have by taking bearing to a trailer shop (not necessarily an auto part store). They have books to cross reference bearing number to find out the axle you have.
And yes, brakes and bearings are kind-of important.
Might not hurt (the first time into them) to have an expert look at them to find out why your at "max gain" to be sure everything is OK.
Like others I also carry a spare bearing just in case I need to in middle of nowhere. Some carry a spare hub because some have to be pressed on and off by machine that might not be available when you need it.
I was at tire shop couple weeks ago (picking up wives car) and asked about re-packing bearings and they wanted $47.00 a hub. I'm sure that price was if nothing was wrong, just re-pack bearings. And not sure how good of job they will do for that price.
Have your elec brakes looked at. Seems high to me to be at "max gain". You might need just brake adjustment or something else that could be serious. Last place you want to be in doubt on anything with your RV is your brakes IMO.