Some guys up here do the opposite in that they ride wings as long as they can hold them up, then switch to a lower/narrower seat HD as age takes over. I thought that the HD’s with the Showa shocks rode so good that they now had a ‘coast-to-coast’ touring bike without modifications needing to be made. Anyway, I like the wing (‘05) for open road cross country travel because it runs so smooth, up or down any mountain, pulling my Bushtec at 80+ all day, without any issue. 2010? If it’s the dark gray, it’s my fav’. Good luck.
Welcome to the forum, if it's comfort and smooth long distance riding your looking for then you can not go wrong with a Goldwing. With the basic service done to these bike you can expect them to last for many, many miles trouble free. The GL1800 has awesome torque and will cruise at 70+mph all day long. A 2010 for 12K is the upper price according to NADA, this depends on the model of Goldwing, if it's the basic model the the high end is about 10K.
Well, after 7 previous Gold Wings and now a 21 Tour, I couldn't imaging going back to a 2010. I traded a 2013 for this one (the best wing I ever had) but the 21 is so superior particularly in front suspension it would be painful to go back. Leaving a 2018 to 2010 I think would be hard as well. That said, a Wing is a different bike but better in my view in about everything I can think of. If you dare, go ride a '21 or '22 if you can find one and see. You might want to take your 12K and 2018 and really move up. Just an opinion but an experienced one. Just Sayin
When I was active Law Enforcement, I trained and rode on the Harley's, but have always owned the GW - a 1984, 2003 and now a 2012. I also ride with LEO's for pleasure, most of whom are own HDs. For comfort and long range riding, you will find the can take the GW many more miles with comfort each day than the HD. I ride from Colorado to either Cali, Oregon or Washington every summer on my GW.
Many have suggested the 2018+ models. Be aware, if you go that route, you will have less cargo space in the trunk and bags than 2017 or earlier. It has been argued that the 2018+ is more of a sport touring than full touring bike.