A 2009 Ram half ton will be payload limited well below its tow rating. The Keystone Outback 301 looks to meet your needs, but I would not recommend that for you. Start with the sticker love2rvcamp listed on driver's door or door jam. It does include full tank of fuel, but no driver or people. Subtract the 625 estimate you have for people/cargo. Multiply by 7 for a reasonable dry weight.
You may be thinking I want a Prime Time Lacrosse 318 but you'll be much happier towing a Keystone Passport 2920. You will likely be compromising things from your wish list.