I guess it depends on what the OP wants.
A Cessna 152 is definitely the cheapest way to build flight time. But it is an absolutely crap machine as regards to X-wind handling capabilities and endurance. I would not recommend it for X-country sightseeing.
On the other hand, short distance flights have the disadvantage of needing more landings, which in Europe incur landing fees.
+1 on not going to Florida. I would not be so negative on California wx. Also, there are some very competitive flying clubs there that offer rentals you simply cannot beat.
+1 on the Midwest.
And the views are spectacular. Check out the Mesas in Arizona; Visit Las Vegas; The river banks of the Missouri; just about the entire state of California; Oregon and Washington; etc...
If the Avgas price in Europe were reasonable, you would of course do France, Italy and Spain instead.