Fort Worden State Park [1] (360/385-4730, www.parks.wa.gov [2], $33–38 full hookups, $19–21 tent, $7 extra reservation fee) has 50 year-round beachside campsites and another 30 near the conference area. All of these sites accommodate RVs with full hookups. A mere five primitive tent sites are available, as are coin-op showers.
Four miles south of town, Old Fort Townsend State Park [3] (360/385-3595, www.parks.wa.gov [2], $17) has shady campsites under tall firs along Port Townsend Bay. It also has showers. The campground is open for camping mid-April to mid-September only.
RVers can park at the private Point Hudson Resort on the beach (360/385-2828 or 800/826-3854, $35 full hookups) or the campground adjacent to the Jefferson County Fairgrounds (4907 Landes St., 360/385-1013, www.jeffcofairgrounds.com/camping.htm [4], $20).
Links:
[1] http://www.moon.com/destinations/washington/olympic-peninsula-and-the-coast/port-townsend/sights/fort-worden-state-park
[2] http://www.parks.wa.gov
[3] http://www.moon.com/destinations/washington/olympic-peninsula-and-the-coast/port-townsend/sights/old-fort-townsend-state-park
[4] http://www.jeffcofairgrounds.com/camping.htm