Need hauling advice, 2019 Tundra SR5 Plus long box

Hi all, first post to the forum... excited to be a new member of the Tundra family! I'm somewhat concerned about hauling with it, though, and I'll explain why below. I'm hoping to hear solutions to ease my fears, or at least be told not to do what I'd like to do so I can move on to figuring something else out.

First off, I'm Canadian, so all reference to dollar amounts are in Canadian dollars. With that out of the way, here we go!

My previous truck was a 2007 F150 XLT that had some kind of heavy-duty package that made it a 'heavy half-ton' (sticker payload capacity of ~2200 lbs) but it had some serious rust/corrosion issues and I was dumping money into it like no tomorrow just to keep it on the road.

I'm super happy with my Tundra, but I'm concerned about the payload cap of ~1300 lbs, nearly 900 lbs less than my old truck. The reason for this concern is that I still want to be able to haul my old 70s vintage truck-bed camper (8', fits in a long box with the tailgate closed). I also have no idea what this camper weighs because there's no weight given on the manufacturer's decal (it's a Vanguard P80, which if Google is correct appears to be a 1977 model).

I know this camper is very likely to be overweight for the Tundra and probably should have a bigger truck under it, but honestly I just couldn't afford a bigger truck. Toyota was giving a hefty rebate ($8k) on the '19 Tundra so I was able to pick it up for $38k, whereas bigger pickups I was looking at from GMC/Chev started in the $57k CAD range, much too rich for my blood.

I'm wondering what experiences others have had with their Tundras when it comes to after-market shocks, adding leaf springs or air-bags, that sort of thing, in order to get more from their truck with regard to payload. I'd sure be disappointed if I'm totally screwed out of using my camper with this truck, but it's also fine if that does end up being the case because I couldn't afford a bigger truck anyway. If I have to I suppose I could sell the camper and get a lightweight pop-up or something, but if I can at all avoid that I would certainly like to. I love my ancient camper.

Thanks all.