I'm considering purchasing a GPS navigation tool and first am looking for observations about the screen clarity and readability. Considering the Garmin GPS 65 or 64. (Should I consider the 66?) I'm older and my eyes have been getting progressively worse. When in my canoe, I have trouble seeing small lines on compass, as well as small print and small detail on maps . Will The GPS screen give me the same frustration? Where do users mount the unit in their canoe or is it hanging from lanyard your neck? All advice most appreciated.

Full disclosure, I have limited experience. Old unit was a Magellan SportTrak. Prob would have used it again, but can't find software for it. Just pulled the trigger on a refurb 66st. Biggest screen that I could justify the $$ on. Also looked at the Oregon 700/750. Biggest difference that I could see was the touchscreen. It is readable, at least, sitting here at my desk. Haven't had a chance to take it in full sun yet. Not sure we really see the sun in February in Indiana. Note that the "st"s do include topo but not very detailed. I think it's 100K which is probably detailed enough for Bdub paddling. Guess you have to purchase the 24K. Previously, used the Magellan to load portages and campsites. Same this time with the 66st, except I just loaded the full file having the memory capacity.
It does find the satellites much faster that the Magellan, but that should be expected with 10+ newer technology. Can't speak to battery life yet. As long as a couple AA will get me to camp (base camp and day trip), then a couple will get us home. Considered the rechargeable option, but a battery block is heavier than the extra GAs.
I hang/attach to my pack/PFD. Glance at it every once in a while to check relative direction. No court martials around here for failure to zig zag. probably a bad joke, apologies.

I'm running at the 70 mark this year, wera trifocals with a healthy myopic correction. Use my Garmin 62 without problem.
these are screenshots from the 62. The others mentioned are simmilar some larger like the 66.

butthead

Never had a problem with details on my 62st or 64st, even in bright sun except maybe some temporary screen glare when at the wrong angle. And, that's while using a screen protector sheet, which usually cuts the sharpness a bit. 66 year old eyes.

Thanks for input. Very helpful to finally pull trigger on a GPS. After weighing options, decided a simpler unit would meet my needs, so purchased a Garmin eTrex.

Had the 66st and after 2 hours it blacked out on me and would not work anymore, guess others have the same problem. It had a nice screen but way too many programs etc for me also.
Bought the old and true 64st and absolutely love it.

I use a Garmin Montana 650t. It has one of the largest screens in the handheld GPS industry 4”. I also have bad eyes and the Montana is easy for me to read. It is very readable in direct sunlight or the dark. It has a super bright display with a lot of Pixels. You can zoom in if needed with the touch of your finger, (touch screen).

I use a caribiner and clip it to a pack in front of me. It then becomes a moving map. It has all the campsites and portages marked so for me it’s a huge help. I also clip it to my PFD sometimes too. I rarely ever look at a paper map now.

If you want a bigger screen than 4” on the Montana 680t, there is one that is bigger. The Montana 700i has a 5” screen and satellite communication feature. It all depends on your needs.