Re: What topics/labs would you include if limited to 5 or 10 days?

You have a lot of scope is my first thought here. Although you do not have an incubator most mesophiles such as E. coli that grow optimally at 37 oC will grow well in the lab at 20-25 oC just more slowly. The most obvious sphere to study however would be the environmental world where the ambient temperature is cooler. Throughout this reply I will reference sites on the web that have the lab write-ups that you would need.

1. One of the first labs I would do is to give the students a mixture of 2 unknowns. Tell them to separate the unknowns by streak plating and then try to ID them using a variety of staining procedures with a bank of reference slides. Stains to include would be Gram, Capsule, Endospore.
2. Isolation from the environment. The isolation of Azotobacter and Streptomyces from the environment is really fun and easy. Just use the correct media.
3. Antibiotics and disinfectants. There is of course the classical antibiotic disk method that is widely used. However, one adaptation which works very well is the growth curve with ampicillin. Grow up 2 flasks or E. coli to OD 0.4 and then amp (100ugml-1) to one. Amp stops the cells forming a new septum but not growing. They increase in size till they burst. You can follow this with OD, or what is really spectacular is by wet mount microscopy. The cells grow really long then start to burst in the next 10-15 min.
4. Food Microbiology. E. coli in hamburger has become a major issue and would be a good way of demonstrating why we need to cook meats and that microrogansims are everywhere.

So in summary: Cover basic techniques in a problem solving way 1), apply to the real world in food and ecosystem 3) and 4), and finally try to include labs that demonstrate why things are 2).