@Water Dancer For the route you are considering (Coastal from Beaufort NC to Florida,) I don't think I'd consider Radar a Luxury. It may not be essential, but for the traffic you are likely to see at night that doesn't have AIS, a modern radar interfaced with your charter plotter might not be a necessity but its more than just a luxury. Isn't night time your real concern? If you can't see a large ship in daytime then you are not keeping a good visual lookout. On the "near shore" passage at night you will see a lot of lighted buoys, lights on shore, lights on fast moving power boats, slow moving fishing boats and the like. Further out, say 50 miles, you won't see the shore lights and probably not many lighted buoys, but you will see a lot of confusing things. Sorting them out can be confusing and difficult. Radar can help with that, but only if you get to know it and use it properly. It is best to fire it up when you don't need it during the day so you can see the radar images from slow moving ships, fast boats, big boats, buoys, shore line, etc. Of course if you don't practice with it it won't do you much good. As you can see, we sailors have our own thoughts and respect the opinions of other like
@dlochner. I think he is correct that AIS send/receive is essential but I wouldn't say radar, if properly practice, understood and used it more than a luxury. I don't know any Navy Surface vessel and commercial transport vessels that doesn't operate their radar when in congested waters. There must be a reason for that. DO NOT OPERATE under the assumption that having AIS alone will make for safe navigation in congested waters especially at night.
Like, I said, you should choose your equipment for where you are going to sail and what kind of traffic you expect to see and how to detect it, analysis it and avoid danger. Even on off shore you may be in coastal shipping lanes as well as "crossing" inbound/outbound shipping lanes at least in Charleston, Savannah, some other lesser Georgia Ports, Jacksonville, FL and so forth. AIS is probably essential to feel comfortable in or near the shipping lanes but I am not convinced it is as useful in off shore less than 50 miles for sorting out the visual image you'll see at night.
Each to his own