Camping:

Campendium

Free Campsites

Michigan Public Campsites

RV Park Reviews

RV Parky

Allstays

Destinations:

Americas Quietest Routes

iOverLander - submit, amend and find destinations

Outdoor Michigan-Public and non-profit locations & activities

Roadside America - Guide to Offbeat Tourist Attractions

Maps:

Bing Maps

Google Maps

Graphhopper Routing Map - Car

Graphhopper Routing Map - Bike

MapCarta (OSM & WiKi, uses webgl)

Mapquest

Open Route Service Map

Open Street Maps

Open Source Routing Machine Map

Wifi Access:

Michigan Open WiFi Map - Connected Nation