Will the enlarger be a permanent install? If not, you might get a sturdy cart with locking wheels to put it on. I actually have my Beseler 23C iii on wheels. I use it on the ground, which is good enough for me. It allows me to move it quickly in and out of my bathroom. Recently, I built a darkroom out of an old bedroom (not dark enough for film, for which I still use the bathroom, but good enough for paper). I have a Beseler 45MX permanently set up in there.
4x5 enlargers are great, but they're also really large and heavy. If you don't plan on ever doing large format, I'd skip on enlargers that size. I can't even get my 45MX in and out of a room without taking it apart. My Besler 23Ciii is much smaller and does up to 6x9. It's a lot more manageable.
As far as accessories go, you'll probably want a darkroom timer and a grain focuser. I don't know that you'll need a paper safe. I used to have a couple, but got rid of them because I never used them. I just keep paper in their original boxes (with the original plastic bags folded over) and never have any issues. This also helps me to know what paper is in there, and how old it is. You might also want to get a stopwatch or kitchen timer to time your development and/or fixer. You'll also need an easel to keep your paper flat during exposure. You'll probably also need some multigrade filters and a place to hold them, and maybe a red safe light filter for the enlarger (if you plan on dodging and burning). And don't forget a drying rack or clothespins to hang the prints to dry.
Some other things to consider are an air blower, some nitrile gloves, maybe an antistatic brush or blower, old towels, print squeegee and glass plate to squeegee off excess water, and perhaps a print washer. I DIY'ed my own print washer and it saves me a ton of time and hassle. A good thermometer is also handy, but may not be necessary for paper. It would also be a good idea to come up with some way of leveling the enlarger. I made a DIY laser alignment tool, but if you're not too picky, you could use a bubble level or even a long ruler.
Really, the list goes on and on depending on your budget and how involved you want to get with all of this.