In the above be aware that the Norcold fridge 12v upper limit is 15.4v
Check out PowerMax as replacement for Magnetek--bestconverters.com (they have other brand substitutions too--just don't get the Ultra111 WFCO or you will be sorry, or the 7300 "upgrade kit" which is better than the 6300, but still has limitations.)
Anyway, another approach for lighting is to use CFLs in your 120v lights if you have those in your RV.
We have three 120v lamps, dining table and a scone each end of the sofa. I replaced the scone lamps with CFLs and when the inverter supplies the 120v for one lamp the 12v draw is 1 amp. With the double overhead 12v light doing the same job it is 3 amps. And that CFL throws more light than the overhead 12. Good reading lamp and lights up a good sized area.
LEDs have their place obviously, but you can reduce your battery draw quite a bit using CFLs on inverter. If the inverter is on anyway to watch TV or power your speakers to listen to music while reading, the 120v CFL lamp is a good choice then too.
If your rig does not have any 120v lamps to swap for CFLs, you can just bring an ordinary 120v lamp from home and use that as a reading light with a CFL in it.
LEDs are not the only way to solve the problem, but they work too of course.