Thanks, Lisa, I agree that C and F make the most sense to me.  My tuning is CGG and having the C and F chords in both keys is a great way to keep this simple.  It will be a lively song for a jam on death and I want to start in C with the verse on melody string only, then across the strings for the chorus, ending on C for a measure, then Bb (suggested by Jan Potts since it's in F) for a measure and then F for a measure (or those two, Bb and F, maybe only half a measure each), before starting the chorus on an F chord for the chorus a second time, but in F.

It also gives me an ending with a measure of F, then half each of Bb and F.

What I really love about your suggestion is the link!  I plan to prowl that site like crazy.  I am at an awkward stage with the need for either arrangements and/or learning how to do my own.  There's even a bit of a story to it.  (My playing sometimes uses the excuse of "Now you know why I am a storyteller and not a musician.").  I now handle the rights to the songs and arrangements of my late aunt, Norma Andersen.  Her musical world was Barbershop, but I bet she's approving my own musical journey.  Thanks for nudging me a bit further.

Maybe this helps?  http://www.secretsofsongwriting.com/2010/05/18/3-smooth-ways-to-change-key/

What I'm getting from it, essentially, is the chord sequence C  G  Am  C7  F

Although to my ears it sounds fine to play the tune in C, strum the C chord for a measure, strum an F chord for a measure, and then start playing the tune in F.  The C and F chords are common to both keys.

Key changes need a bridge to transition and Robin Thompson suggested I take this out of "What Are You Working On?" and start it's own discussion.  I could try this in Music Theory, but am interested in how to do this and, maybe, others have wanted to do key changes in a song.

Yesterday I asked:

I am currently trying to develop When the Saints Go Marching In.  I am using Ionian tuning and want to go from the key of C to the key of F. Might anybody be able to suggest a bridge?