Allison, while the Navion is a fine aircraft some things to consider,
1. Its an old aircraft, most built in 1946 or 1947
2. Parts availability
3. Only 345 on the FAA register, so rare and maintenance shops that know the aircraft/systems would be few and far between
4. Go for some thing more mainstream - Bonanza, Mooney, 182RG
Get in touch with
Navion Society Home, they mention a book authored by Dan Brodie "WHAT TO LOOK FOR WHEN BUYING A NAVION."