Toronto to Las Vegas in my G1

Hello everyone,
I am going to make the utterly crazy trip of driving from Toronto, Ontario to Las Vegas, NV in July. Before I leave, I am going to give little Prius a once over. My Gen 4 navigation suggests a route that will take about 36 hours, while my Chrysler Navigation suggests a far superior route that will take only 31 hours and almost 2oo kms less driving. Be that as it may, I have decided to take the Prius anyway, even though the Neon will give me at least 700 km's per tank, while Prius I generally am able to get about 900 or so.

I have a little list of to do's and wanted a sanity check from everyone to ensure I am going to do this right.
1) Change transmission fluid (I do this every 60,000 kms)
2) Change Oil and Filter
3) Change cabin filter
4) Check all fluids (I changed the inverter fluid and rad fluid about a year ago)

I do get an occaisional PO402 code, but I usually clear it with my scanner. I intend to do this as economically as possible, so I am going to shoot for 45 mpg or better. I can usually do about 115 km/h and she will hold at about 45-46 mpg.

In terms of stops, I am considering taking a 5 hour snooze every 12 hours just to keep fresh. Also, can anyone confirm that truck stops have showers and are open to regular motorists? Any other suggestions for taking a shower?

I intend to update my progress as I go, with pictures and updates to keep everyone interested. I figure this will probably be her last BIG trip. Your advice on preparations is appreciated.