I don't like to have to change lenses in the thick of things, so I use wide-to-tele zooms. Started in 2006 with a Nikon D50 and the Nikkor 18-200mm zoom, which is a great combination of camera and lens. Later, I upgraded to a Nikon D7000, and the 18-200 started to show it's posterior on the more resolute sensor, so I got a Nikkor 18-140mm for the D7000 and put the 18-200 back on the D50.
I found going over my travel photos, that I split my shots between wide and tele. For wide, I usually rack it all the way back, most are at 18mm; for tele, the majority are racked all the way out but a significant number are between 80 and the max focal length, probably reflecting my usually poor attempts to properly frame a composition. It was almost never about 'reach', I find I don't miss the extra 60mm of the 18-200, until I go to shoot something like a bird.
I hear a lot of good about the Nikkor 18-300mm, and the Tamron equivalent. Thing is, with any of these superzooms, your're going to probably be less enamored with any depending on your camera's resolution. When I put the 18-200 back on the 6MP D50, it looked great again in my small web and photo-album JPEGs. The 18-140 on the 16MP D7000 does the same. I hear (roughly) that the 18-140 looks okay up to 24MP. If you have the opportunity somewhere, you might want to take your camera and shoot a few images with the available lenses, take 'em home and see how it plays.
Regarding weight, I find that less challenging than the size of things, competing for space in my backpack with computer, water, wife's things
. Well, starting to notice weight at age 60, ask me again in 5 years...
FWIW