I have RM and like it. B&G is more race/sail oriented - Being that old your current instruments are most likely SeaTalk. Current instruments use NMEA 2000, which is just starting to be phased into an Ethernet version. All major vendors are N2K even the SeaTalkNG ones. If your sounder/paddle wheel/wind sensors are still ok - you can save $$ by installing an ITC5 from RM which will get them on SeaTalkNG a conversion cable from N2K
If you have a below deck auto pilot that can also be reused - just get a ne controller. The new ones like the RM EVO are so much better than previous generation.
If your getting RADAR the important thing is get one with Doppler. Then desire if you want a pole on the stern or mount on the mast. Mine is on the stern.
Also get AIS Transmit - it allows the big commercial boats to “see” you.
I also recommend getting an engine monitor from either Actisense or NolandEngineering (RS11, I have this for my old M25 Universal). This puts the gauges up at the helm where their readable, and alarm thru the MFD’s.
I also recommend using a single vendor if possible, so you can update firmware and configure things.
In addition to my RM I have a few Yacht Devices products (temp, barometer, logger, WiFi bridge).
Geeze. All I can say to that is that Admiral and I sailed out of Bayboro Marina, St. Petersburg (Tampa Bay) along the coast and through the waterways of southwest FL between Pine Island Sound and Tarpon Springs for 11 yr using a binnacle compass, depth finder, pair of Fujinon 8x30s, a paper chart kit of southwestern FL, and the local cruising guide, with occasional help from a finicky LORAN C unit. No RADAR, no GPS, no AIS, and certainly no supersized cockpit chartplotter.
There’s not much fog in SW Florida around Tampa Bay, hardly any. So, RADAR isn’t needed as in foggy venues. Probably why the boat does not have one already. Regrettably, a lot of one’s transit along that coast is via the ICW. So, with a paper chart and binoculars you just read the numbers on the daymarks to find out where you are in the channels. The markers are not so far apart that you need a chartplotter to stay in the channel. Twisty channels may have range markers to assist.
The commercial Bruisers are not in the ICW. The ones that come up Tampa Bay do so toward the middle, pretty far from sailing areas on the west side. There aren’t that many of ‘em. Not like here in Long Beach. At the Sunshine Skyway Bridge you may wish to wait to let one through, rather than pass under the bridge span. He doesn’t really need to see you. He’s staying in the dredged channel (otherwise he’s aground). You need to see him, and know where you are relative to the marked channel, etc. It’s your job to stay out of his path; stay out of the channel when one is coming in. You don’t need RADAR for that. Cruising along the coast you principally need to know your depth to estimate your distance from shore lacking GPS or other fixes.
So. The most important navigation equipment cruising SW Florida is paper chart, guide book, depth finder, binnacle & hand bearing compass, and binoculars. A small hand-held GPS would, of course, be VERY useful and I do recommend having one or two aboard. Certainly cannot hurt. But, you’re not talking thousands of dollars here. Wait until you decide to go somewhere where you need all of that e-capacity. For more fun, you’ll want a good dinghy and reliable outboard.