Definitely go with Art's suggestions, unless you're convinced the front muffler and axle pipe are good. I too am committed to not seeing a mechanic, and I must say, the only job I hesitate tackling is the exhaust system. If you only have to deal with one rusted connection, you'll be much better off.

Be aware that when the U clamps are put on connections, they typically compress into the inner pipe, so that even if the rust of a joint is broken free, it can still be tricky to slide the outer pipe off (or slide a new inner pipe into a previously clamped outer pipe). Some parts outlets (Canadian Tire in Canada) do free tool loans; I borrowed a tailpipe expander to use on an old outer pipe.

You may want to invest in a small torch, although it's not like having acetylene. A suggestion I haven't tried is to heat rusted joints for a few minutes, and then flash them with cold water. The sudden temperature change can help to "crack" the joint.

Another suggestion involves tools: a Dremel tool, or a grinding wheel on an angle grinder, to cut along the length of the outer pipe on a rusted joint, if the outer pipe is just being discarded anyway. The outer pipe can then be peeled away, reducing the contazct area and making it easier to hammer apart.