Rory, Sean drove his little hyundai (with a canoe strapped ontop of it) down that road just fine. Although, it was later in the season when conditions were a bit dry. If it's early season and snowmelt runnoff is all over the road, try your best to avoid the washouts. I would say you would be able to do just fine if the conditions are right. However, if you cannot make it to some point, turn around and park your car in Polebridge and put up a thumb, you don't want to park anywhere on that road because it's so narrow and the chances of blocking somebody is inevitable.
If the road fails, but you can access places around bowman or quartz lake, make rainbow or carter a backup plan! They are well worth the trip (if you're into paddling or a semi-ruff bushwack along the shore).