As fun time says, it's a pain in the a$$ to replace some of those isle light bulbs so, knowing that they were kind of a pain to find, I went to www.superbrightleds.com
and looked up replacement bulbs for them in LEDs. Those bulbs are called "festoon" bulbs. There are two kinds of festoon bulbs. One has what's called "bullet" ends (looks almost like an old glass fuse only the ends are pointed) and the second type of festoon bulb has what's called: wire ends. Those are loops of wire that "hook" onto the fixture contacts on each end. If your bedroom closet is like ours in our '04 Itasca Horizon, you will find wire ended festoon bulbs behind each closet door.
I changed the isle light bulbs in the forward (next to the entry door) light, and the one at the entrance to the rear bedroom. As for the one in the kitchen area, yep, as fun time says, it's really a pain to change that bulb. So, what I did was change the entire fixture to one that looks like this:
It was a piece of cake to install. I drilled the hole for the wires, removed the wires from the original isle light and attached them to the new wires and that was it. That little tiny fixture puts out very nice light but, is not overpowering. After all, it's an Isle light and is for guidence in the evening. And, since those original festoon bulbs are like any incandescent bulb, THEY GET INCREDIBLY HOT, I no longer have that problem. I can leave those isle lights on for decades and there's almost "0" heat from them.
I used LED replacement festoon bulbs in the closets too. Now, no heat in there either. Just something to think about.