I bought an RL in May 2005 and have nearly 35,000 miles on it. I spoke to another guy at work the other day about his RL, he's had it for a few months. He said he was not getting good gas mileage. He asked what kind of mileage Ive experienced. I or my wife, who drives it more than me (for her job), checks the gas mileage everytime we fill up. We consistently get over 21 (usually 21.5 - 22) miles per gallon and that's with 20 inch wheels. Because the wheels are .89 inches taller than stock we have to adjust the odometer reading by 3% for an accurate assessment. He asked how it was possible we got that kind of gas mileage and we said we don't drive like we're always running late. In fact, in order to get better gas mileage we've both become less aggressive. On the 70 mph interstate I probably average 65-68 mph. Anyway, he said he'll not be so heavy on the gas pedal at stop signs/lights.
A day or so after our conversation I happened to end up driving behind him in my economy car, 94 Altima. Holy crap did he drive like he's traing for NASCAR. He stopped hard and fast and accelerated like he was trying to lay rubber. I had a hard time catching up with the guy. Made me wonder if those who are reporting poor fuel economy in the Ridgeline are driving like this guy. Also, my bro-in-law liked the vehicle he got one a while back. He reports similar mileage to mine but only on the days/weeks he's not driving like a douche.
I recommend a hitch rack for the RL but if you don't mind taking off the front wheel the Save-a-Load bar (Saris Kool Rack) is nice.