Okay, I just read you introduction (nothing like starting backwards is there?) It sounds like you do have a good base to start from you are mainly chaning directions with your clowning. Ralph Dewey has a line of little books that run in the $5 and $6 range that have a lot of good information.
www.gospelmagic.com (If that doesn't work Google "Doc Haley magic") not only carry Dewey's books but a number of others in that price range that are useful.
When planning a solo show you have to structure the show a little tighter than you might when working off the cuff with a partner. Your interaction will now come from the audience itself and your props instead of your partner. Think about how you might be able to engage your audience. For example: I wanted my audience to realize I was a fun, slightly "confused" character without taking time away from my show and I also wanted to do something for the audience while I was setting up and getting ready to start. Serendipity struck. I bought an aluminim framed director's chair for the children to sit in when I am face painting them, It just so happens to be just wide enough for my show box to sit on the seat. Now I don't need a table and I don't need to bend over to get in the trunk. As I'm setting up I talk to the audience a little bit and I place something on top of my case. Well withoug looking I open the lid and what ever is on top slides out the back of the chair. I pause confused and then see what fell. I now pick it up and "place" it behind my box while I look inside. The first time it falls on the floor everyone thinks it is an accident, by the third or fourth time plenty of people are laughing talking to me. Now I am ready to begin the show and my audience is already warmed up and ready to participate as my new "partner."