My wife and I took the time to drive both a Gen 1 Taco and a 2008 Ridgeline yesterday. It was a bit of an apple vs oranges comparison as the Ridge was an RTL, so much more upscale than the Tacoma. We should've compared the Tacoma to an RT or a Sport, but hey.
So, this is what I gathered.
Pros for the Ridgeline.
1. Yes, the Ridge is much more comfortable inside. It's wider and the back seats feel the like back seats in a sedan. The backseats in the gen 1 Tacoma are as comfortable as getting kicked in the a$$ by a wild donkey.
2. The Ridgeline is faster and drives more like a car. In fact, it drive better than both of the Xterras I've owned. The visibility is great too.
3. The interior amenities in the RL are much more posh. Like I said, we drive an RTL, but still, I guess that even the RT is more posh than the Tacoma inside. Putting a center console seat with a lap belt (which is something my wife wants to do for the rare event when my parents come to visit and we need 6 seats) is much more doable in the RL than in the Taco.
Pros for the Tacoma.
1. This one's opinion: Ok, I admit... I like the Tacoma more for 2 reasons... I like the truck feel and the styling. I've always loved these trucks and always wanted to own one and never have. It's simpler and kinda stripped out... That's actually something I like. Of course, my wife prefers the gadgets. She actually likes a lifted truck with slightly low offset wheels and black rims, so if I buy her the Taco I have to give her that. But not a problem, I love that. She still likes the RL more nevertheless.
2. The MPG thing is still in favor of the Tacoma... I really don't want to get anything under 15MPG and I'm fairly certain the RL is going to average us 14MPG in our hilly town with crappy weak gas. After my research I'm pretty sure the lighter gen 1 Taco would give us about 2 MPG better. Plus, the RL's revvy engine will promote ever more fuel consumption over the Tacoma's more rough unit.
3. There are many places to go offroading - here. The Tacoma would be better at that if we decide to do that.
Finding a good gen 1 Tacoma with low miles can be a bit tricky (in the condition I want it to be in) - The one we test drove yesterday is the best one we've come across. The thing was well above average and with low miles for the year, 70,000. It was also price around $17,900 for an '04. It even had the camper shell we need on it. One of the better units too. The RL we tested was a 2008 RTL with 53,000 miles and they wanted $21,999. That one was at Car Max... Good car, but Car Max is always more pricey and they won't negotiate on top of that.
I put in an offer for the Tacoma but it wasn't accepted. It wasn't a lowball offer... I think it was pretty reasonable. Even though the dealer said no, and we walked, it was late at night on the 1st and I have a feeling a small counter-offer today might do the trick to get the deal. But we'll see. I might try and get a hold of a Ridgeline RT that's priced more closely to the Tacoma and take it for a spin. I like the Tacoma more, but in the end, it's going to be my wife's car so I have to keep that in mind.
I am not familiar with any way to put a 6th seat in a RL using the center console as a seat.
There's no way 5 people in the Taco will be as comfy as 5 people in the RL.
The Taco is a better off road vehicle, no question. The RL is a better suburban home-owner vehicle, no question.
Both vehicles have their flaws. Make sure if you get a Taco that it doesn't have the frame rot issue. I'm not sure how you know, to be honest.
Regarding your mpg analysis, remember the Taco is 2wd until you engage the part-time 4wd. Without lockers, it's going to be one wheel driver per axle. The RL is an AWD vehicle and at least has a (semi) locker in the rear. So it won't surprise me if the Taco might get a bit better mileage around town. I doubt it will beat the RL on the road.
In the end, it won't matter how practical a vehicle might be for your needs, if you don't want it, you will probably always find reasons to not like it. So get what you want (or you wife wants, if she's going to be the main driver). Personally, I'd feel safer with my family in the RL than in the gen 1 Taco.