Please critique my plans for a 90day EU trip using the 3 month EURail globalpass

OK thanks…

It would seem then, that this eurail globalpass just doesnt work on any city metro lines?  Like for instance, some time ago I spent a week in Roma and got the metro/bus week pass and really got our money’s worth around Rome that week.

Given our plan is to stay in Florence during the week for these 3 months, we’d need to make other plans to use their metro there, as well as the Roma metro for the week we are there?

I think my main issue here is Im not quite sure what is meant by “real mainline” trains?  Is that the means for inter region/city and not for intra-city then?  If so I’ll need to make additional plans then.

Thanks again!

Indeed. Eurail is a product of all major railway companies in Europe, ideal for local trains (sometimes even intracity trains like S-bahn, TER, R, RB, L, Sprinters,...), interregional, Intercity and international trains. 

The pass is valid on (almost) every train of the participating companies, this is the list: https://www.eurail.com/en/plan-your-trip/trip-ideas/trains-europe/useful-train-information/participating-railway-companies. About 95% of European trains is covered I'lld say. 

If you take a train (or any other type of transport) of a company that is not on that list, your Eurail pass won't be valid and you'll have to resort to ordinary tickets. 

Although on rails, intracity public transport like metro's  (U-Bahn, Underground, Tube, Metro, subway, T-bana,...) or trams are not considered as (mainline) trains and are run by much smaller local companies, and not included in the pass (since they are not in the list mentioned above) .

But these local public transport companies have often a lot of options in their tarrifs. Single ride, 10-rides ticket or 100 tickets (10 rides are usually already a lot cheaper than constantly buying single ride tickets), visit tickets coupled with museum entrances, season tickets of a week, month, 3 months, a year,... The more modern one's you can just swipe your bank card at the scanner and you're good to go. These are usually quite cheap, barely a few euro's for a ride. The fraction of the price of a Eurail pass, you can cruise unlimited on local transport. Since many European cities have an essential social role in providing affordable transport for the locals and want to convince you to not use a car, the extra cost will be minimal.

Just ask at the counter of the local transport company what the best offer is if you stay a weekend/week or a couple of months.

To put in perspective, for the cost of a Eurail pass, I'lld be able to use busses and trams, every day, without any limitation in my home region for almost 3 years long :) 

It's always interesting to compare prices of a pass with advance tickets, but a three months pass is really interesting product for your extensive travel plans!

You should take into account that a 3 months pass costs about 10 euro per day if you'lld take a train every day. And theoretically you can get from Barcelona to Amsterdam in a day  for 10 EUR or take an infinite number of trains to practically anywhere in Europe for that price, seat reservations excluded. Not a single advance ticket comes close to that insanely good value for money. 

Going from my home town to Brussels and back for a work meeting (35 min train ride) with ordinary tickets even costs much more than 10 eur 😅