that is a difficult question to answer. We all have different boundaries and technical experience as well as skills. You can go overboard quite fast.
As you are new to mining, I would suggest you start small, with a few simple set of security features. Over time you will get more experience and implement more, if you choose. This is your decision in the end. No one, including me can ever tell you what you should or shouldn’t do. The goal is to learn the skills yourself.
I would suggest, that you follow some simple rules, in the beginning
- don’t install any kind of wallets on your mining rig
- don’t install any software onto the rig, other than the mining software
- if applicable, keep your Antivirus software current and updated
- only download the mining software from a reputable source (Github or for example https://www.awesomeminer.com/software-list)
- choose a mining pool based on your preference (consider pool fee, minimum withdrawal amount and overall hashrate). Also consider to use a smaller pool to keep the hasrate spread out and prevent attacks
- remember the phrase Not Your Keys, Not Your Money. withdraw the money from the pool from time to time
- if you are technically inclined, you can use the SSL ports of the pool (if available)
For a mining rig there isn’t really a lot of danger. If you decide at some point to run a node however, then you can check back here.
As for the internet connection, I would use a router for your mining and a separate router for your home network. I for example use a different subnet-mask to separate the two.
Hope that helps for a start.