Is this an auto or manual transmission? 2WD or 4WD? I know you have the extended cab because the SR5 trim only came on the extended cab.
Extended SR5 specs:
curb weight: 3600/3620 (2WD manual/auto); 4040/4110 (4WD manual/auto)
payload: 2100/2070 (2WD manual/auto); 1960/1890 (4WD manual/auto)
gross vehicle weight rating: 5700 (2WD); 6000 (4WD)
There's a few screws you need to take out to git to the cluster but still rather easy if you take yer time.
Fer the rear bumper, you could try craigslist.org or even
www.car-part.com and see which yards near you would have the rear bumper. Hopefully it's not too far and you can inspect it before paying fer it. I haven't been a fan fer parts that I can't look at or git piccies of before paying...unless they have a guarantee or warranty on them.