ok, those tires are fine, better than factory actually and the maximum size to use without rubbing issues.
so, the question then is what the heck is underneath as the spare? if it is in fact a HD package vehicle and an HSE, then it's most likely a 19" wheel and worse yet, with a spare that IS factory and will not be usable due to the size being so off what's on the ground.
FYI, if you get a flat while driving home, DO NOT use the spare if it's size is not the same diameter as the 265/65x18 on the ground.
You 'could' use lr4 wheels, but there is no such thing as an lr4 18" wheel in the US market. You would need to go with one of several 18" lr3 wheels which I would suggest if you want the best overall choice in tires and tire sizes and sidewall height for offroad.
Seeing as you have decent tires there already, you could go with lr3 18" wheels, 5 of them, put those tires on, get a 5th to match, then all 5 match wheels and tires.
It looks to me like the valve stem is rubber...if so, you're getting screwed out of $500+ in tire pressure sensors. Even if it was a loaded SE, it still had tpms sensors.
If it is an SE, then the full size spare, assuming it is an alloy lr wheel, is likely an 18". I'll be hoping for you that's the case

A photo would show me what it is. Factory 19" hse wheel from 2006 will be a 6 spoke, SE 18" will be 10 spoke.
I'd still torque those wheels before a long trip home....