Advice for novice on coastal cruising
While these were nice little boats, they were designed as light weight (for their day) raceboats and are not intended as offshore cruisers. My best advice is to look for a boat intended for that service.
If you wanted to take a Pearson 26 offshore I would start with a thorough survey. No matter what the survey showed I would replace the keel bolts, add transverse frames in the keel and rudder area and build a new sturdier rudder. I would remove the large portlights in the doghouse and glass in the holes with a cored material and then add smaller portlights. I would probably raise the bridge deck and close up the dip in the transom for the outboard motor. I would probably replace all chainplates, tangs, and standing and running rigging. I would glass in additional framing forward of the main bulkhead. I would build light weight storage racks that could hold plastic milk crate type storage units for gear and supplies. You also need to increase water storage.
Then you need an offshore sail inventory which on a boat like teh P-26 would mean adding both light and heavy weather sails.
By this time you could have gone out and bought a boat better suited for the purpose and come out ahead.