Guilin is too big to be quite, too famous to be cheap and too far away to the nature.
Overnight in Guilin is not necessary as you can quickly catch a bus to Yangshuo where the scenery is much more beautiful, the atmosphere is more relaxed and you find easily travel facilities for backpackers at a reasonable price.

Anyway Guilin still remains as a top destination selected by most travel agencies for the domestic and international tourists. It is disposed convenient connections by air, train, and bus to other towns in the province and major cities in China.

I visited Guilin once and found nothing worth a recommendation. Here are some sites where you may find some useful information of Guilin:
Chinats.com: 33 attractions with beautiful photos.
Chinavista.com: Brief introduction of scenic spots in Guilin.
Travelchinaguide.com: The profile of Guilin: Location, population, climate, etc.
Passplanet.com: A guide for backpackers.
Asiatravel.com: Hotel reservation. Good discount for some 4 stars hotels.