Yeah - I'm sure I'm a bit biased, but I think that part of the state cutting from Kueka to Seneca to Cayuga is great
To get to Hammondsport you'd get off on the 1st Bath exit (heading west to east) - make your way to washington street, work to liberty street and ride it as it turns into geneva street/rte 54 .... about 7 miles from there to Hammondsport ...... staying on 54 will run you to the east side of the lake towards Penn Yan - taking a left onto 54a will lead you through hammondsport towards the west lake
To get to watkins glen from hammondsport you'd just start up the east side of the lake on 54 - fairly soon you'd take a right and climb up the hill on co rd 87 - you can take that to 96 or drop down to fleet road it really doesn't matter much - they connect at co rd 23 and you split waneta & lamoka lakes (minor lakes) swing through a couple old country towns that show some age (tyrone) - connect to 28 and drop in watkins glen
there is a little pier in Watkins Glen - nothing fancy, but I like to stop when I head back (mainly because I live in a desert now) - there is also a little lake side park
If you make it to the Glen I can't recommend enough to at least walk some of the gorge - try for the whole thing, it's not that long or tough, but definitely at least get out of the car and stick your head in ....... then again, whenever I get back I try to be outside and in the country as much as possible ...... i find it relaxing and refereshing, but as with anything your tastes and mileage may vary
If corning is your base it's only a half hour up 414 to watkins glen, so you don't have to package it with hammondsport, etc
The drive from the glen to ithaca on from watkins glen on 79 is nice, although not much to see
As for coffee - there was a place in Painted Post that I stopped at last time I was home that was really good - heaven or something ....... not sure if it's still around
There may not be a ton of options, but I'm sure there are bound to be some options relatively close to market street
If you hit bath in the morning I'd recommend grabbing a couple English Cuts from Betty Kay Bake Shop on liberty street ... chat a whyle is decent for breakfast and their sticky buns are good
Jelly Beans in Painted Post has a solid breakfast and is open relatively early (6am)
If you get jumpy and a bit brave, there is Smokeys Restaurant at the truck stop in Kanona - about all I can think of in the area that is 24 hours ....... definitely a classic truck stop establishment though
Don't be afraid to ask around for suggestions though - most people in the area are friendly and have an opinion, it could also lead to a couple other suggestions of what is current and off the beaten track