First of all, it's important to realize that we always start out with the presumption that all records are open to the public. That's the way the law is written. Then, if an agency gets a request for something and wants to withhold records, it must defend its decision to do so using the "exceptions" in the Right to Know Law.

The good news is that correspondence between state legislators and lobbyists is expressly made public by what we call a "reverse" exception.

There's an exception that allows the following to be withheld:

Correspondence between a person and a member of the General Assembly and records accompanying the correspondence which would identify a person that requests assistance or constituent services. This paragraph shall not apply to correspondence between a member of the General Assembly and a principal or lobbyist under 65 Pa.C.S. Ch. 13A (relating to lobbyist disclosure).

I've underlined the "reverse exception" part, which makes lobbyist correspondence specifically public.

Correspondence received or sent by other state elected officials is all presumed to be public, with the exception of any material that may legally be redacted or withheld.

Meeting logs, also, should be accessible. I can't conceive of much information in a record of scheduled meetings that could be withheld.

Good luck!