Coachman no spare? BS. Assuming Coachman was gracious enough to install a receiver hitch, use that for a spare wheel and tire. Like this:
https://www.amazon.com/CURT-31006-Hitch-Mounted-Spare-Mount/dp/B0009YIE1O
f you're using the receiver for something else (bikes?) use this:
https://www.amazon.com/CURT-45792-Receiver-Trailer-2-Inch/dp/B00371VLAC/ref=asc_df_B00371VLAC/?tag=hyprod-20&linkCode=df0&hvadid=241915008172&hvpos=&hvnetw=g&hvrand=4505672379815143385&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9027838&hvtargid=pla-571952257097&psc=1