I'm gonna chime in again... I have daily driven my 40 for 15 years, and it is now a weekend warrior for the past 5 years. I am no stranger to rust and desiring a RUST FREE Cruiser. Mine is not rust free... but I LOVE the ol' girl.
If you want a RUST FREE Cruiser, it is only wise to
start with a RUST FREE Cruiser.
If you want to ENJOY a Cruiser for driving around town and exploring trails, then buy ANY Cruiser.
IMHO, if it runs, stops and steers straight it is going to be ENJOYABLE.
Personally the 12HT is one of the best if not the best TOYOTA engine ever produced. I know the purists will boo-hoo this, but I feel ANY cruiser can be wildly enjoyed, driven and even cherished if the owner has the right mindset. I think we see some uber nice examples of rust free beauties out there that have either miraculously survived or have had big $$$ thrown at them to bring them back from the depths. The average Joe on a modest budget can get into a modest cruiser with average rust issues for an average price. Then he can enjoy the joking thing.
I'll say it again, if you want to end up with a RUST FREE Cruiser then START with a rust free one.
If it isn't a big deal to you, the options that open up for you are nearly endless!
On a side note, I do agree with the other posts that if you are looking to restore this particular cruiser back to all steel original condition you are going to loose your wallet in that pursuit. Now, if you take a body class at your local tech college and give it go, you could end up WAY better off for minimal investment but it still won't be cheap. The average car restoration of classic or hot rod cars usually budget about 1/3 of the overall cost to the body work and paint. To do it right, straight and shiny takes some serious coin.