Wayne,
Undecking a boat is not an easy task, even with the right equipment AND experience. The easiest part is removing the rubrail and separating the bond between the hull and deck joint. Driving a small pry bar in between the hull and deck will separate the 5200.
The problem lies in the bonding surfaces that you can't get to. When a new boat is in the decking (some call it capping) process, polyester adhesive "bonding" putty is applied on top of the stringers and b/heads, enough so that when the deck is lowered there is quite a bit of squeeze-out, hence a fairly large bonding area. Now if the stringer/deck surfaces were sanded (prepped) properly, that putty will have a death grip on the surfaces it is adhered to. Virtually impossible to separate without serious mechanical means. Usually when we have a hull replacement warranty boat, and we want to save the deck, we will cut very large holes in the hullsides to allow us access to the inboard stringers to first cut through the putty as best as possible with a sawsall (bunch of blades!), then put some upward pressure on the deck with the hoist and get the 6' prybar and 20 lb. sledge out to finish the job...and you do this the length of the boat!
I think you would be better of trying to cut out the portion of the sole where the repair is, then glass it back in...