Welcome to the TM family!
And now a page from my history book...
We have a 2002 Tahoe with a tow rating of 8700 lbs, a good 2000 lbs more than your Lexus. Now, the story:
There is more storage room in the TM than what was in your pop-up, so it will be very easy to load it up, combined with loading up your LX-470. On our first bigish trip, we ended up going over the rear axle weight limit of our 2002 Tahoe. I was surprised we did it, but we did. Part of the reason was that we had 3 adults + 2 kids, my wife packed a ton of water and canned foods. We were underweight overall as far as the GCWR was concerned. This is probably the number you need to worry about most, and is not usually advertised. The second number you want to find out is the GAWR for each axle. A lot of people forget or ignore this number.
Bill has a good explanation of these terms here:
https://www.trailmanorowners.com/for...ead.php?t=9655
Lesson learned, weight adds up very quickly.