I'm late to the party.... Been out camping!
I see you have a fix in place. Good. As was said, the scissor jacks are not intended to lift the camper to the point the tires are off the ground even if they might. They can exert some pressure but not in the amount to lift the camper that high. They can fail or unscrew. (yes, enough weight and they will unscrew)
Leveling out the camper left to right has several options from home made to store bought. In my case I did the home made. I use short 2 x 8's for my tire size. They are a little wider than the tire to allow for some misalignment and the tire still be all on the board. I have a double set of 3 heights for one side of the camper ( 6 boards). The ends are cut on a 45 to allow the tire to roll up on them easier. And the lengths of each are such that I can stack them and the 45's allow a transition from the longer to the next size all line up.
See this pic from our prior T2499 which is smaller then our big T310SR. This setup will be closer to yours.
There is a 3rd board that will fit on top if needed. And I have found if I have to ever get up that high, I use my 4 wheel drive down in low low 4 x 4 (granny gear) Then the rolls right up. If not the board can slip out of position trying to get up on a 3rd block.
I have now beveled both ends of the wood blocks and moved them to the big camper. See here now moved to our bigger camper
The length of the boards is such that even when stacked I can slide them in between the tandem wheels so I can set them before backing up.
You may also notice the homemade wheel chocks. Since the tires are off the ground conventional wedge chocks do not work. These made out of 4 x 4's with a 5/8" or 1/2" threaded rod and a deep socket on a ratchet work very well. The bottom of the all thread is jam nutted in place to the lower block. The top block a clearance hole. They help take some of wiggle out of the camper and the camper is not going anywhere. I use the chocks on both sides of the camper. And do not forget to take them out when you pull out. All 4 wheels will drag....
Others have used a long board to go across both wheels. It has some advantages and and some draw backs. The main draw back is the long board will "pop up" sometimes when you pull off the board. If your camper has a dump valve right behind the tire, you can crack the dump valve. I tired the long boards once, and mine has that dump valve right behind the tire. It flipped up and bang it got hit. But I lucked out and did not crack it. But I learned it can and others have broke the dump valve that way.
But... like all things, what works for some does not fit all. I have a good camper buddy who uses the long boards all the time (years) and has not had an issue. His layout does not have the dump valve right by the rear tire so it works for him. So the long boards do work if your camper setup will allow it.
If you ever need to go up higher then 3, (1 1/2" x 3 high = 4.5") boards, then you need a different setup. 2 boards cover 90% of all our camping. 5% I need the 3rd board. The other 5% I need to get up on over 6" high. I have pics of how to do this if you need. Let me know. It can be done easily and safe but takes preplaning to know that site is that bad and you cannot or do not want to change sites.
OH, and I will make one recommendation!! If camping in the camper is getting more fun by the trip, start now letting Santa know that a power tongue jack is on the "list".
Bad back, = need a power tongue jack. Once you convert you will "never" go back to the "crank"....
Hope this helps
John
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