Another one I've been working on for months, but when I went to play it this Afternoon, drew a blank (Duh!...)..
A little sentimental, but pretty and usually popular -

"Me Ain Dear Galway Bay"

Nothing you'd want to dance to, but it rolls right along and the lyrics evoke a lot of nice imagery. I do it in "D", but then I'm a Baritone.
Normal people might want to kick it up to "F" or even "G".

When I got to the Residence a half hour early to set up and tune, etc., about 17 "Grammies & Granpas" were all seated in the Recreation room waiting for us.
The first thing they wanted to know was "Did you bring the dogs???"

Of course "Maggie" and "Baer" our two little sibling Yorkie-Poos (AKA "The Hooligans") were out in the van while I lugged in my stuff, and soon joined the party, much to the Resident's delight.

We did a lot of faking and winging it, and threw in a few Sea Chantys and gospel favorites etc. when I ran dry of Irish tunes that I could remember the chords & lyrics to... Switched off to the whistle & flute when the left hand went numb from chording the guitar.

They all sang along to "Danny Boy", BTW; they usually do.

The Hooigans ran around begging shamrock cookies off of the folks and getting loved on by their host of adoring adopted "Grandpeople", little bob-tails wagging freneticly the whole time. (They are about 12 pounds each).

All in all it went really well, and for the $50 that they pay for these gigs (about monthly) it's about the most lucrative "career" in music this ol' Uncle is apt to have any time soon, we reckons.
But throw in the smiles and the hugs, and the check ain't the half of it.

Shucks; I even got a standing ovation as I toted the ol' Yamaha out - not bad when half of your audience is in wheelchairs, eh?!

I hope that you have as much fun at your gig, Claire!