Here's a route taking in all the road passes in the Lakes. It includes the following:
Wrynose Pass - east/west
Dunnerdale
Ulpha Fell
Wasdale
Hardknott Pass
Wrynose Pass - west/east
Greater Langdale
Red Bank
Thirlmere
Derwent Water & Borrowdale - north/south
Honister Pass - east/west
Buttermere
Crummock Water
Whinlatter Pass
Newlands Pass
Honister Pass - west/east
Derwent Water & Borrowdale - south/north
Ullswater
Glenridding
Kirkstone Pass & The Struggle
Wrynose and Honister Pass are driven both ways. Although the detour into Wasdale is not a logical part of the route, it's a worthwhile addition to it.
Total Distance: 140 miles
Total Time: Depends when done - best early morning or evening. Slow and tedious during the day in high season.
Scenically the route includes the best of the Lake District.