They're designed to be walked on, but I have no idea what the max might be.
Pretty sure it's able to support at least 200lbs.
Without disclosure, I've been on mine a few times without incident. We have the IQ or Profile type of roof, no cab over.
I would suggest to cut a 2 ft X 2 ft square of 3/8" or 1/2" (max) plywood to use as additional weight distribution when working on your roof. It's not too large to be able to get it up onto the roof and it's easier to place around the roof areas where you need to work. Stay away from any cut outs as much as possible.
I am 230. I have been up on the roof of my view regularly with no problem. The antennas will break frequently, I replace at least 1 each year. I also scrub the roof and lube the vent hinges periodically. You will be fine.
I spent some time on the roof replacing my antenna with no problem. I also waxed the top in Mexico and there were 2 guys up there cleaning and waxing.The roof had oxidized over the years. I believe there is a 10 year or lifetime warranty on the roof. On my 2007 view, I replaced the crank up antenna with the new saucer style. Very easy change. Just had to widen the hole a little. Totally recommend it as you never have to worry about not cranking down the antenna.
I’ve been up on the roof of my View IQ many times to power wash, wax, and replace the antennas.
Just as recommendation, I replaced the rubber duck antenna with 14” metal whip style that thread right onto the 6mm thread. Got the pair for about $25 on Amazon. Reception was much better after replacement also.