The key can be collected from Strahan visitors centre and your vehicle will be inspected for mud. I don't think there are any car wash services in Strahan but there are some in Queenstown.
The road for the most part is in reasonable condition, the worst part I think is the descent past Mt Mccall and would probably not recommend without low range.
A few steeps climbs that are rutted out might be an issue without decent clearance and no 4wd but you could always walk from there.
I havent been for a while but there are a number of recent videos on youtube -
https://www.youtube.com/watch?v=e3h5v3Nkyf0&t=94s https://www.youtube.com/watch?v=52OjD6KTgPs&t=1635s (16 minutes mark)
Hope that helps
That looks like a pad.