The roof should last a long time - usually far longer than you are going to own the camper. I wouldn't look to replace it.
Here's what I do to maintain it. Keep in mind two things:
1) Not only does the manual recommend periodic checks, but its a requirement that you maintain the roof for warranty purposes, which I believe is 10 years. 2) Your Shamrock should have a TPO roof so the maintenance is for that type.
Get a tall ladder and climb up on roof (It will support your weight). Use a board if you want to (I don't) and step clear of A/C, vents, skylight, etc. A pair of tile setter knee-pads are highly recommended to make this job much more comfortable.
Inspect all seams, gaskets, and any place that the roof material has been cut or drilled. Check closely around A/C, vents, antennas, sewer vent, and all side seams. Look for any signs of bubbling in the membrane and any tears (damage from tree branches, etc).
I use an Alpha product for sealing cracks in the existing caulk, which I get cheap through my dealer or Dicor 501 Self Leveling will work and is a lot easier to find at Amazon. Do not use silicone. You shouldn't have to remove the old caulk unless something is really wrong with it.
If you want to clean the roof, Alpha specifically recommends Murphy's Oil Soap for their TPO roofs. Its safe. You want to stay away from any cleaner with petroleum in it.
You do not need to treat it like is recommended sometimes to provide protection for EPDM roofs.
Hope this helps!
DW, 3 Kids and our Goldens
2012 Shamrock 233S
2008 Toyota Sequoia 5.7L 4WD