I would paint the paneling as you would typical walls, paint the crown and base in a typical trim color, and then do a lighter version of the wall color on the ceiling. I would also consider having the fireplace refaced. There some companies that do this for a steal and it can completely change the room!

I would get some lighter colored furniture and rug and some good lighting that panelling looks expensive to me.

Move in and live with it for awhile. It may grow on you. Don't be too hasty to do something that cannot be undone.

If it is winter there, the room will be at its darkest in the next few months. Here are some ideas to live with the panelling for a year or so before deciding if you want to paint. See if you can replace the bulbs in the recessed fixtures with something brighter. Add $15 uplights in each corner to brighten up the whole place and show off the panelled walls. Check to see if any overhanging tree branches outside can be pruned back successfully at this time of year.

Add a light rug with light upholstered pieces and several floor or table lamps.

Then look at changing the type of recessed lighting. New fixtures designed for bright LED bulbs can be installed, if the house doesn't have that kind already.