Shanghai is pretty hot and humid in the summer (think New Orleans but a little warmer).
Shanghai does not have much in the way of historic/tourist sites, but it’s a great city to wander around in. Even better if you can ride a bicycle.
For trips outside the city, I highly recommend Shaoxing as an overnight/weekend kinda place. I really liked it and recently went there for the first time. Train is probably easier than driving. Actually, I wouldn’t recommend driving as the “rules of the road” here are probably pretty different and it takes a while to feel comfortable.
I also recomend visiting one of the river towns. Zhujiajiao is the closest one, and frankly after having been to half a dozen, they all look about the same.
Brush up on Mandarin. You need a phrasebook with the pinyin (romanization so you can take a stab at it), English and Chinese characters altogether. You’re not doomed if you don’t speak Chinese but of course it’s better if you do. You could also just speak Shanghaiese in this area.
Definately go see the Shanghai museum. There is also the city planning building that’s pretty cool.
Vegetarianism. I was one for many years in China. The trick is to say that you’re buddhist (are you)? and do not eat meat. Most Chinese just can’t comprehend vegetarianism, but buddhism and not eating meat does the trick. There are famous buddhist vegetarian restaurants, and you can probably google them. Gongdelin is one. Also check out www.thatsshanghai.com for restaurant listings, bars, things to do, features, etc.
If you are a buddhist, then I would definately recommend Putuoshan, which is where Guanyin came to earth. Monastaries there have some pretty rocking veggie food (as most do throughout China). Putuoshan is actually an island with some decent white sand beaches. The beaches around Shanghai are lame - don’t bother as it is just a big stinky lake with all the drudge that comes from the Yangzi River (think mississippi outlet).
Shanghai can be real cheap if you’ve got a place to stay and go pretty local, or you can spend a lotta money. Just some reference, the subway costs about 50 cents depending on how far you go. Taxi’s cost $1.25 for the first 3 km, and if you’re in the city center area it’s hard to go much over that. McD’s basic fries, big mac and coke costs $2. Maglev costs $6. Big bottle of Tsingtao beer is 40 cents.
When you planning on visiting?