My wife and I both had Tacoma's, V6 4x4 5spd extended cab (1999 and 2004). We absolutely loved those trucks, we both had close to 200K miles on them when we sold them, and sold them at almost double blue book value. We sold them due to the size, we have two dogs and just the two of us. When we went camping for anything more than one night we were so loaded up it was not comfortable. A crew cab taco would have made it a lot better. The newer Tacoma CC are quite nice, but still not as much room as a full sized. The older 3.4L V6 got between 13-18 depending on what, where, and how fast. I use to tow a 20' comp ski boat a lot, it struggled in every aspect of towing (I completely re did the suspension and it helped a bit but still sucked at accelerating, hills, and stopping). Aside from towing I absolutely loved my old truck, and cried when I saw her drive away. We've had 5 adults (each less than 200 lbs) in a newer Tacoma crew cab, and it was tight and uncomfortable for all three in the back.
We bought a 2007 Chevy 2500 diesel CC...I now smile every time I drive anywhere. There is so much room in the cab its awesome. The bed feels like it is a foot wider and a foot deeper, more room to spread things out and keep it below the bed line. We regularly have 5 adults in the truck, all are extremely comfortable. Empty I get between 17 and 20 mpg. Maintenance is a bit more (but not much since I usually changed my oil every 3k miles on the tacomas...5. qts) Chevy: 10 qts of oil (every 6k miles), fuel filter (every 6k), fuel treatment (6oz) every other tank. We wanted more room for a future family, and wanted to be able to put a pop camper top in the bed, and tow the boat. The new truck is great for road trips, great for hauling, great for my road rage

, great for additional passengers. The only thing it isn't great at is things that little cars/trucks are good at....tight back roads, tight parking lots, parallel parking, and zipping around town.
Do you plan on tent camping, how much do you camp with...pretty minimal or everything including the kitchen sink? If you (and your wife) pack pretty minimal, I bet you can do with just a Tacoma. But as the kids grow up and want to bring a friend along, or have more gear (toys) to bring a full size will be a lot nicer.
With all that said I am very glad we upgraded to a full size, but I will always have a special place in my heart for Tacomas.
Another thing to look at is Dodge is suppose to have a Diesel in their 1500 lineup soon....might be worth to take a look at that.