Two locations with the same email has been perfectly fine. As Bruce mentioned, the Portal only comes into play when you're connected to you local network. So hitting portal.hubitat.com when at location 1 shows only the hub(s) on the location 1 LAN, and hitting the portal at location 2 only show the hub(s) on the location 2 LAN.
Managing my remote location has been a breeze as well. I have a VPN setup so I can remote in if I need to (seldom). I have cloud dashboards set up for both locations so I can quickly and easily check on sensor status, unlock doors and open the garage remotely if I need to let a contractor in, etc. HE has been super reliable at both locations and I have zero regrets.
The most fragile part of the setup is my internet service. It's never gone down (that I know of) but it's the most likely point of failure and having my cable modem or router hang while I'm 600 miles away would be pretty disastrous. To prevent this eventuality I'm using a Digital Loggers Web Power Switch. These are available for under $100 on Ebay (I snagged one for $80) and can be setup to Auto Ping one or more reliable IP addresses such google's DNS servers. If the Web Power Switch doesn't get a response after X number of attempts each N minutes (both X and N are configurable) you can have it power cycle one or more of the 8 outlets. Mine power cycles the modem and router. I also have the HE hub connected to one of the outlets just in cases it locks up (never has at either of my locations). Should it ever happen, I can VPN in, browse to the Web Power Switch using my browser, and power cycle the outlet that the HE is connect to.
Lastly, one thing I never do is HE firmware updates remotely. I've never had an issue with updates locally but I'm certain Murphy's Law is in full effect when attempting remote firmware updates.