Moab up to Green River then Hwy 24 down to Hanksville. Head west on Hwy 24 to Torrey, turning south on Hwy 12. After Bryce Canyon, take Hwy 89 south to Hwy 9, which will take you west into Zion. This route, while all paved, takes you through/by all 5 National Parks and passes many opportunities for off roading. Potash to Schafer trail in Canyonlands is awesome. Hwy 12 is spectacular. Lots of options for fun side trips.