Here's how I winterized my 2000 Scamp 16 in the fall of 2006.
Note: this procedure does not require a water heater bypass kit.

1) Fill fresh water tank. (I know - this step doesn't make sense - read on)

2) Go to dump station and rinse black and grey water tanks.

3) Park trailer. Place on jack stands if desired.

4) Empty remaining fresh water in the fresh water tank.

5) Drain water heater.

6) Close fresh water tank drain valve. Pour 2 to 5 gallons of non-toxic RV anti freeze into the fresh water tank

7) Turn on fresh water pump.

8) Close valve on water heater inlet once the pink stuff has filled the heater inlet line.

9) Open cold water valve at shower. Run until non-diluted anti freeze is coming out the shower head. Pump out through the drain pump and into the gray tank to protect drain pump and drain lines.

10) Fill toilet fill valve until non-diluted anti freeze shows up. Dump it into the black tank to protect the tank.

11) Put shower head in intermediate position so the shower head is not open. Open water heater tank drain. Open cold and hot water at shower. Close hot and cold water at shower when anti freeze comes out of water heater tank drain. This step back-feeds the hot water line from the shower to the water heater.

12) Open cold water at kitchen sink until anti freeze appears. Open hot and cold water valve at sink, and cover the faucet with your palm. Pump until anti freeze solution appears at water heater drain. Close cold then hot valves at sink faucet then remove palm. This step back-feeds the hot water line from the sink to the water heater.

13) Open water heater inlet valve for a few seconds again to be certain anti freeze is protecting the water heater feed line. Re-install water heater drain plug at this time.

14) With the water pump still in the run position, press in on the check valve on the city water fitting. Hold in until un-diluted anti-freeze appears. 

15) Optional: Drain gray and/or black water tanks again.

Click here to see the procedure used in previous years

The fine print: All standard disclaimers plus the following disclaimer apply: Only you are responsible for the consequences of using this information. Not Dan Meyer, Scamp, RVIA, Yahoo! Groups, any government or government agency of the United States of America, or any other inhabitant or organization of any kind in the known or unknown universe not listed will accept the responsibility for your use of this information. It is completely up to you to determine how you use this information and by visiting this web page you do accept all  responsibility for any and all consequences of your use or non-use of this information. This information applies even if you do not read or understand this paragraph.