And abetterrouteplanner.com (which is technically a European creation, so hopefully you are familiar with it) works very well in the US as well, and you can set it up to look for CCS stations as well if you will have a CCS adapter available. Plus, the car will be able to route you to Superchargers while on long distance legs.
But yes, for general exploration of public chargers (including L2), Plugshare is your best bet. It has a Trip Planner capability that you can use for example to show you charging stations located near certain amenities (such as hotels or restaurants), so you can use that to help with planning overnight stops. If you are looking at chain hotels, Hilton properties are by far the most common to host charging stations (Hampton Inn & Hilton Garden Inn especially). If B&B's are more your style, those are more likely to have Tesla destination chargers.
As for payment, that really varies, but again, consult Plugshare for payment information. It will tell you what network (if any) and what the cost is. Many L2 stations are free, but by and far, ChargePoint is the most common network, so at a minimum I would sign up for a ChargePoint account. For DC fastchargers, you will most commonly run into Electrify America, EVgo, and again ChargePoint, with Blink and Shell Recharge possibly showing up. There are roaming agreements between networks, so for example you should be able to use an EVgo station with your ChargePoint account, but I don't have first-hand experience with this myself. Electrify America stations can be used without an account, but their credit card readers are a common point of failure, so I would probably establish an account if you are looking to use that service. But really, you should be fine with just the SuperCharger network, destination chargers, and a ChargePoint account for any pay L2 stations that you may encounter.