Thanks for the quick response - that has basically been what I've figured, but still have some stress about the situation nonetheless.
Any Toyota engineers out there, to help validate my smell test?!
Forgot to mention something that may have actually brought my payload overage of 225 lbs down quite a bit. By loading my heavy 6V batteries and loaded cooler towards the back of the trailer behind the axles (200 lbs + 115 lbs or so), I should be reducing my tongue weight quite a bit thanks to the teeter totter effect. With a starting point of approx. 730 lbs (loaded trailer tongue weight + 12V battery + weight of propane in tanks), I'm assuming that I don't take enough weight off to negatively affect driving safety/handling.
But I didn't factor this into my payload weight yet because I haven't actually measured the difference in tongue weight. Thinking of building a DIY scale like this to do so:
https://www.youtube.com/watch?v=nMoLA44lcgU
I'm also trying to slim down by 10 lbs, so wish me luck with that!
