This is an excellent idea. I have considered doing something similar, and I may actually begin to move in this direction, perhaps getting down to two bodies (one color, one b&w). With my five bodies, things can get complicated and confusing.
I would agree that 800-speed film is not necessary. The highest I go is 400, and, with very rare exception, it has always served me well. I like Kodak Portra 400NC and Ilford Delta 400.
I think it's a great idea to simplify one's life and encumbrances in such a manner.
I traveled throughout Southeast Asia in the 1970's with one body and one 28mm prime lens. The film I used varied by what was available in local shops but in those days that was pretty much ASA 100 color print and occasional slides.
The new Kodak 800 color film is wonderful. I can't believe how small the grain is and I got gorgeous minilab prints from my recent rolls. Two weeks ago I took photos at the Hoover Dam in Nevada's blazing sunlight. The 800 worked great and I didn't need any ND filters. As long as your camera can do 1/1000 on the shutter you should be good to go.
Keep the small flash with you for those occasional indoor night shots and you should have everything covered.
Have a great adventure !!