Keep this in mind if the plan is to go larger with the tires and regear. One kind of negates the other. The larger diameter tire acts like a an OD gear slowing the engine speed for the same road speed with the same gearing.
Playing around with an online gear calculator to see where you would need to be to maintain stock like feel with larger tires.
https://www.crawlped...calculators.htm
The ring and pinion calculator is a good way to see what you have, input the new tire size you want to run and it will suggest the ratio to compensate for the increase in tire size. Meaning it's going to behave like stock, but not really add too much extra torque over what is compensating for the larger tires. I'd suggest if you want more power (at the expense of highway cruise RPM) to take what the caluclator says for larger tires and step up to the next higher numerical ratio available. If it say recommends 4.10's, go to 4.56's, or if it recommends 4.56's, jump to 4.88's.
Like others have indicated the higher numerical ratios do have some strength issues as the pinion gear looses teeth at the numerical ratio increases. But, sticking with good quality gears and professional setup should keep things lasting.
One thing not really discussed (I'm surprised too) is the aero drag from these campers. I noticed it big time with mine. I'm running a 5.3 Vortec in my K5 with a FWC and it made a huge difference in mileage and power. Pre-camper the 5.3 pushed my K5 around Colorado with 4.10 gears and 35" tall tires without too much issue. I was averaging 15-16 MPG on the highway too. I put the camper on and I noticed aero drag requiring more throttle to overcome the wind. Throw an uphill grade and it got worse. My tire size was great for keeping my cruise RPM lower even with the 4.1's, but the RPM was low enough I was almost 1000 RPM or better below peak torque. It caused sooner downshifts to maintain speed and keep the RPM closer to peak torque.
I've felt the drag when driving into the wind to be so much I had to downshift to 3rd and leave it there until the winds calmed. What this means is if you do plan on re-gearing, use a gear calculator and go the next gear up from the target to gain a little torque on top of the tire size change.
I could use to move to 4.56's in mine to compensate, but I'm going to install a 7.4L big block to overcome the lack of low end torque from my 5.3. The peak torque is lower and comes in sooner so it will limit my need to spin the engine to the moon to build the torque needed to get the truck/camper rolling down the road. Granted swapping engines isn't a realistic idea on a late model Toyota, but bump in gearing will help a lot. You will continue to rev the engine too the moon though.