If you're early and can't check-in yet, here are the local places with wifi. All are free, but it is best to support businesses providing this service with at least a minimal purchase.
Guerneville:
Sonoma County Library Guerneville
14107 Armstrong Woods Rd, (707) 869-9004
Safeway: In Starbucks seating area.
16405 Hwy 116, (707) 869-9433
Coffee Bazaar: Café, Indoor and outdoor seating, also has computers (pay to use)
14045 Armstrong Woods Road, (707) 869-9706, www.mycoffeeb.com
Stumptown Brewery: Restaurant/Bar, Inside and on deck.
15045 River Road, (707) 869-0705, www.stumptown.com
Main Street Station: Restaurant/Bar
16280 Main Street, (707) 869-0501, www.mainststation.com
Monte Rio:
Take 2: Café, Outdoor seating
Bohemian Hwy & Hwy 116, (707) 865-4190, www.monte-rio.info/donsdogs.html
The Village Inn: Restaurant/Bar, Indoor and outdoor seating
20822 River Blvd, (707) 865-2304, www.villageinn-ca.com
Northwood Restaurant: Restaurant/Bar, Inside and on deck
19400 Hwy 116, (707) 865-2454, www.northwoodrestaurant.com
Rio Nido:
Rio Nido Roadhouse: Restaurant/Bar, Indoor and patio seating
14540 Canyon Two Rd, (707) 869-0821, www.rionidoroadhouse.com
Forestville:
Sunshine Roasters Espresso Bar: Cafe
6656 Hwy 116, (707) 887-1632, www.sunshineroasters.com
Russian River Pub: Restaurant/Bar
11829 River Road, (707) 887-7932, www.russianriverpub.com