We just purchased a 7 year old coach last September.
-Checked that all things worked prior to purchase.
-Applied new caulking to entire roof.
-Treated all rubber with 303, including seals, gaskets, hoses I could reach.
-Did basic maintenance items (engine oil, generator oil, oil filters, air filters, fuel filters)
-Replaced all bulbs with LED
-Removed all valences. Built new valences and window treatments. This was fun and started to put our own personality to the interior.
-Recovered dinette cushions.
-Installed new mattress.
Still to do:
-Reseal all exterior seams on side walls and slides.
-Install basic solar (already own)
-Install TPMS and valve extensions
-Get RV GPS
-Get tow bar for flat towing
-Get wall decor.
I suppose the list will go on and on. :)