Ther are many things to do in The STL - we have one of the best Zoos in the country and it is free admission (I think it is $8 to park in one of the lots but there is also free street parking, and you can get passes to do the train, childrens zoo, seal lion show, stingray feeding..) If you do go to the arch, buy your tickets online ahead of time and print them - there is usually a LONG line to go up to the top once you get into the arch, having your tickets already you get to bypass most of the line, (a park ranger inside can help you) --- There is also Grants Farm, The Botanical Gardens, The Science Center/ Planetarium and The Magic House. Lodging really depends on where you wnt to be 6 Flags is about 25 - 30 min outside if downtown in Eureka - the zoo, city museum, arch, are downtown (well the zoo and science center are in in forest Park).