"Overall, it has worked fine as long as the users talk to each other about owning the files."
Since QB 2015, you install the QB Database manager Hosting Service on the server or hosting system, to manage File concurrency and to Lock records. That is a significant change.
"With Windows 7 support ending in 2020 and Quickbooks 2012 not being certified for Windows 10"
QB 2012 reached end of life in May 2015. You are 4 years Late. And now your file is 7 years behind current. You should ask Intuit to update it for you. Or, you need to take it through interim updates: QB 2013 was a Major Revision year, then 2016-2019 and Rebuild in between each jump.
"so I am hoping someone can give some suggestions of what specs would give a solid experience for users (CPU, RAM)."
Did you google: QuickBooks 2019 System Specifications
"Also, is it even worthwhile to get a server for this small of an office?"
You can use a Peer host, but one of the systems has to Host the file and run that app at startup. You no longer allow the Program to act as file host.
"Also, there will be times when two users will want to remote in to work from home. Besides doing some sort of remote desktop connection to a workstation, are there any other suggestions on how this might be handled?"
They cannot both remote into the same computer system at the same time, though. And they won't need QB installed locally. They are going to access an office computer and drive it like a zombie.
Thank you for the feedback.
I did search for requirements before, but the page I had found at that time did not specify client or server.
I am a little confused on why they would put the processor requirements simply as "2.4 GHz Minimum"and leave it at that. That means a Pentium 2.4 is fine? Also, they don't mention what level of hardware would provide a good experience...I don't want an entry level experience, but I also don't want to invest in cutting edge hardware when I am fairly certain that is not necessary for our needs...which is one reason I made this post. Do you have any suggestions on server hardware or hosting system for a 3-5 user office?
I am not too worried about the data conversion at this point. We have to go through the process regardless, so we will just force our way through it.
"Do you have any suggestions on server hardware or hosting system for a 3-5 user office?"
I'm not an IT professional. We are QB peer users, here. You need to work with someone who can evaluate your entire office requirements.
"I am not too worried about the data conversion at this point."
It's not Conversion. It's Update.