I'm doing some signing.

[grarpamp]

On Sat, Sep 23, 2017 at 1:40 AM, jim bell <jdb10987 at yahoo.com> wrote:
> encryption since the 1990's, not much even then, and then I used PGP

Regarding your old keys, if you still have access to them,
you should either revoke or self-sign them as appropriate,
for which revocation may be the most prudent choice.

> I realize that I don't have a public key available; I'd like to publish it,
> but there probably haven't been any key-signings nearby.

Having a public key signed is not a prerequisite to publishing it.
Well unless you count self signing, which is not strictly necessary
either, but of such importance that gnupg does that operation upon keygen.
You can iteratively republish as more signatures come in.

> I'd like to prove who I am.  At least initially, I though of using a Skype
> call, jimbell887, to talk to a few of the more credible people around here.

Sure someday. Though that gmail address you copied is an unknown.

> That will, at least, reduce the level of doubt until I can get up to speed
> on this very irritating software.

Mailvelope is a browser plugin based webscraper.

https://www.mailvelope.com/

If you have access to IMAP/POP and SMTP (each over TLS),
either of the two below may be of interest and are likely
more stable / reliable / secure than mailvelope.

https://www.mailpile.is/
https://www.enigmail.net/