Decided I'd go the cheaper route and just replace the rear crossmember rather than doing a full bumper. The bumper isn't really needed/$2k for one isn't in the books at the moment...but that rust certainly doesn't care.

SO, ordered the crossmember and endcaps this morning. Part numbers for anyone interested (though they really weren't too hard to find):

51209-35211 Cross-Member $287.97
51391-35090 End Cap $16.76
51392-35080 End Cap $16.76

McGeorge Toyota ended up having the best prices online. ~$10 cheaper for each end cap and $20 cheaper on the crossmember. 3-day shipping for it all was also only $27!

Hopefully these can be put on before the end of the year. Doesn't seem like too wild of a job - we'll have an assortment of cutting tools and a welder at our disposal. But if anyone has recommendations - particularly around making sure things are aligned - I'd love to hear em!