I always travel with a full fresh water tank. (and sanitize once a month). Figure 8 lbs per gallon and see how much weight it adds. You're probably okay.
Start your list with what you can think of now and add as you go. It will develop to a useful one in a few trips.
I always keep a slip of paper in my pocket a day or so before a trip and write things down as I think of them in addition to my standard list.
Keep a separate list for towing that you can check in a minute or so before you head out. Lights checked, hitch pin in, safety chains hooked, brake breakaway hooked up, etc. Even when you think you no longer need it, use it just in case. My F150 with max tow actually has this check list on the digital dash.
I have a camping log too where I have a "things to do" list as something comes up that needs to be done later so I won't forget. I take care of those on the non-camping weekends
Paul & Sheri - Upstate New York - SUN-0258
Amateur Radio KD2KCY - VHF 146.520 MHz
2012 F150 F/X 4, 6cyl EcoBoost, Max Tow pkg
2013 Rockwood 8280WS 5th wheel
2006 Sunline Solaris T-1950