'07 XK Coupe. Completed travel from Salem, OR to Indiana by way of Santa Fe, NM and Kansas City. Return through Chicago and Minneapolis.
Average speed was 60 mph. Drove at 5 mph over limits, except 55 mph zones where cruised at 65 mph. Speeds ranged from 65 mph to 85 mph.
Overall gas mileage was 25.7 mpg.
At least 6.5% of mileage was city driving. Just driving through Portland, OR rush hour lowered average speed from 65 mph to 60 mph.
Gas mileage on non-city portions was over 27 mpg. Typically, my city gas mileage in light traffic is about 18 mpg.
I'm 75 years old and found the seating very comfortable, and easily did 700+ mile days back-to-back. Wife never complained about discomfort.
The small luggage hooks near rear seat are very strong and easily support a clothing rod zip-tied. However, space requires hanging garment to be hung at an angle instead of the usual 90 degrees.
Trunk capacity held two 21" roll-on bags (too big for carry-on) plus room for additional small items, like a case of wine.
I have the 2012 navigation update. Found the alternate routes offered to be limited and dull. Navigation screen suffers from reflected glare making it unreadable at times. Need to tilt it more vertical.
Roads ranged from ungraded dirt near Los Alamos, NM to freeways.
Power for passing was always adequate, but never breathtaking. Car was a little wheezy at 9,000 ft.
Stock exhaust is very quiet at cruise, and is a good balance between noise attenuation and power. Road noise is a huge factor in driver fatigue, and the XK suffers. Many years ago, when I was working, I did a lot of long distance air travel, and found that ear plugs (and later noise-cancelling headphones) greatly reduced travel fatigue. I have installed sound deadener throughout the Jag's interior, and it has helped reduce road noise. Most of the road noise is from tires. New tires "slap" less than old worn tires and are quieter. Still, road noise in my Jag borders intolerable on OR freeways (studded winter tires allowed in OR reduce pavement to a gravel texture). Did a ride over loud pavement with a GMC pickup, and the GMC was much quieter. I think location of rear wheels away from driver's ears makes a big difference.
I also have a 2014 Hyundai Equus, which is comparable to a Lexus 460 (test drove both before purchase), particularly in road noise attenuation. The Equus is a much more comfortable road car than the Jag, but I think this is obvious.
Saw no Jaguars or even XKs in our trip, except in Chicago. I suspect most Jag owners do not have the time to take long road trips (retirement benefit). The XK is unrecognizable to most in the hinterlands.
Traveled extensively in NM mountain roads. Usually, I drive at no more than personal 7/10s on unfamiliar roads. I always switched to "sport setting", and found it useful. It doesn't change the nature of the GT auto to a sports/track car, but definitely settles the car better in the twisties.

 

Wow!
Rey,
How long did you take on that road trip?
Guy

 

Trip began June 19 and ended July 10 -22 Days. 12 driving days - about 465 mi./da. on average.

 

Just traced your route on the map. Looks like a great trip.

Agree with you about the glare on the Jaguar Navigation screen. I got the update disks for a recent European trip but then preferred using my Indago combined SatNav and speed camera detector.

Graham