Yes, rust is a problem with 02's . Remember that the newest one was built almost 30 years ago.
Having said that, there are cars in AZ, NV, CA, etc. with very solid bodies. 1976 cars can be had for great prices in CA due to their smog laws.
Like you say, an E30 3 series might also be amn alternative. They are cheap and plentiful and a lot less rust-pronr than the 2002.