Tas driving distances/useful towns

Hi - please excuse some disoriented mainlander distance questions - we're trying to figure out an itinerary and I can't get my head around the distances/road terrains. I trust locals more than google maps - so here goes....
1. Google map is telling me it takes 3.5 hrs to drive from Hobart to the start of the Walls of Jerusalem start via Mersey Forest Road. Could that possibly be correct?? Would you do that and then start walking?? I am very dubious....(and a late riser)
2. Would you drive from Hobart to Mt Field - do a half day-ish walk and return in one day?
3. If we finished the WOJ and then drove around to Cradle camp site - Google is telling me 1 hr and 7 mins - oh hahaha - really?? Is there a town between to re-stock in?
4. Or if we were around the WOJ and wanted to head over to Freycinet - half a day??
If these times are correct you guys are lucky lucky lucky
We are not the kind to start early/finish late....Thanks for suggestions!
1. Google map is telling me it takes 3.5 hrs to drive from Hobart to the start of the Walls of Jerusalem start via Mersey Forest Road. Could that possibly be correct?? Would you do that and then start walking?? I am very dubious....(and a late riser)
2. Would you drive from Hobart to Mt Field - do a half day-ish walk and return in one day?
3. If we finished the WOJ and then drove around to Cradle camp site - Google is telling me 1 hr and 7 mins - oh hahaha - really?? Is there a town between to re-stock in?
4. Or if we were around the WOJ and wanted to head over to Freycinet - half a day??
If these times are correct you guys are lucky lucky lucky

We are not the kind to start early/finish late....Thanks for suggestions!
