I'm in the same "senior, retired" boat you are and I've decided to do as much traveling and photgraphing I can do for the next few years. I'm probably a little more into photography than you may be, but I'll give you a couple of things to think about.
Do you want snapshots for memories or photographs to ooh and aah at? There's a lot of $$$ between the latter and former. My first dslr was a Rebel XT and a Tamron 18-200 zoom on a cruise to Greece and Turkey. I, and my friends, loved the photos from the trip. It wasn't until I went on my first photo workshop to Rocky Mtn. NP that I saw what much more expensive lenses and equipment (and experience) can do, but everything is relative. I live in the hot South and I didn't know what air conditioning was until I was 12 years old, and it was a window unit in the bedroom. Now you wonder how you ever did without it. My point is if you've satisified with your photos with your equipment, use it. If the Kodak is "large" like someone suggested, you can buy a Canon P&S that fits in your pocket for a couple hunderd dollars. I think my daughter has an SD 800 (no viewfinder-- only an LCD). It makes great photos and you can stick it in your pocket.
I remember several months ago an avid photographer begged his daughter and her husband to take some of his higher-end equipment on their trip to Europe, but instead they opted to take a $ 50.00 camera and loved the photos they got.
I'd take all the Canon stuff you have and a tripod. I've been to Rocky Mtn., Yellowstone/Teton and Yosemite and am going to Glacier this summer and I think the tele you have will be long enough.
The only suggestion(s) I have if you want to (or fell like you should) upgrade would be (in the following order):
1. 24-105L lens- good all-around lens, but not wide enough for panoramas. You would have to change lenses, but not often.
2. 40D camera- New technology, much better viewfinder and LCD, live view, etc.
3. 70-200L f4 IS- Small and compact for a tele and one of Canon's best lenses (if not the best for the money.
4. Maybe a 1.4 teleextender if you see an elk, bear, bison, etc. at a distance
A lot of what you'll be doing is driving and parking to go to a "must-see" site. I carry my camera and lens around my neck and use a Tamrac slingbag for the extra lenses, batteries and CF cards.
Good luck and have fun,
Kent