Rally cross ... and private property . I'm super lucky in that my crew cheif owns 600 acres. also BLM land, FS roads , OHV Parks , etc.
Excluding rally cross and private property with owners permission , You can't go driving on public lands at full on rally speed , nothing even close .
Also this has been a big part of my success and good finishing rate (I'd tell you what it is, but I don't want to jinx myself) Driving your rally car to work at least once , hopefully 2-3 weeks before a rally.
I've found issues a few times doing that .. lost 2nd gear a week before Idaho in 2009 or on my way to work. dropped the car off to be fixed @ lunch and picked it up after work, and drove straight to the rally (this was back when i was Cool (low budget) and drove to events)
Talk to Ross Wood. He seems to regularly set-up test days in Ontario. Not the cheapest way to test, but the most secure and legal way to run on actual stage roads.
Our test days in Alberta are all well subscribed and have proven to be valuable learning tools for drivers of all levels.