In addition to the excellent suggestions already posted by Ron and Ted, I'd like to add a few comments:
1. Baja trailer - worth every extra penny in ease of launching and retreival. Get the side guides - makes retrieval in windy conditions a cinch - the boat lines itself up perfectly on the trailer every time and doesn't hit the dock. Get the tongue jack with the wheel too.
2. Reef points: 1st reef point at about 2'5" from the foot gives you a 25% reduction in mainsail area for winds over 18-20 knots or so. 2nd reef point at about 4'9" from the foot gives you a 50% reduction in mainsail area for winds over 25 knots or so. (or reef at lower wind speeds if your skill level is not high)
3. Mainsail slugs (IM calls this a capture system) - makes dropping and reefing the mainsail on a P19 much easier.
4. Jiffy reefing - IM installs a single line system (one rope per reefpoint) that makes reefing much easier and faster. It works very well. (Personally, I prefer a two line system - it's a little more work, but does a slightly better job of shaping the sail, also slightly less wear'n'tear on the 1st sail slug above the reef. I can reef to my 1st or second reef in under one minute without leaving the cockpit)
5. Backstay - this probably should have been #1 on my list. I wouldn't sail on the ocean without one personally. Keeps the mast from pumping when going over swells on a downwind point of sail. Keeps the forestay tight when pointing -- helps you point a lot higher with a straight jib luff in higher winds. Recommended by CDI if you get a CDI roller furler/reefer.
6. CDI roller reefer - a matter of personal preference. Some folks prefer a regular forestay rigged with a downhaul. However, I love the CDI on our boat. I never have to go onto the foredeck to change to a smaller jib if it gets windy.
7. Marine VHF radio. In my opinion, a necessary safety item.
Our P19 is rigged so we never have to leave the cockpit for anything except setting the whisker pole or docking. ALL the lines are run aft to the cockpit via a plate at the base of the mast with turning blocks and then to rope clutches. As soon as I get a tiller tamer (or autopilot - wishful thinking!) installed, it will be fully equipped for single-handed sailing.
Regards,
Judy B
P19 Fleet Cap'n, Potter's Yachters
1985 WWP19 #266 "Redwing"
Sailing San Francisco Bay in 5-35 knots of wind, 2-5 foot swells, and currents up to 6 knots.