Hi Steve.
You face similar challenge to me back in 2012, retired, decorating done, garden tidy, now time to get the old girl back on the road, bike laid up for 29yrs in my case, complete strip is only safe way to treat these old girls.
As already mentioned sludge trap is the killer, to get a clue of its condition just look in the bottom of your oil tank.
Best of luck, plenty of help on this forum.