Two days you'll be fine anyway, you'll get it all done.
however, I always find it best to start at air in Forbidden Valley, then walk the park anti-clockwise. Forbidden Valley, Gloomy Wood, Katanga Canyon, Mutiny Bay (generally for food), then cut by the side of the lake to Ugland and Rtia, then Hex, then X-Sector, then to Spinball for the end of the day.
You should get a ride on each doing it that way.
People always head to Rita or Spinball to start off with, then they hit Forbidden Valley later in the day - so you're best avoiding those early and then getting to them later. However, Rita's queue is always pretty huge, as is Spinball's. Oblivion can get big if there's a breakdown/stoppage.
Remember, the queues shut, but the rides don't. So if it says "Ride close is 6:00", then that means you can still get into the queue at 5:59, even if it's an hour queue. This is useful for getting a ride on Spinball or Rita as you spend the closed time queuing, rather than missing out on another ride.
Also, though it contradicts what I've said above (depends on priorities), Nemesis tends to get a tiny queue about 45 minutes towards the end of the day. So it's the best time for re-rides.