I don't have a BOB, but I have done a bit of camping on a solo-no-hotel cross country trip. I think you really need something to address sleeping, yes I know a "real" man would just sleep on dirt and a rock as a pillow. And YES I've done that too, for fun and other times because I had to. You can do it a few days but you never really get quality sleep after 3-4 days and with uncomfortable, insect riddled, night animal creeping on you for your heat, mosquito crazy nites, your productivity during the day gets shot. I suggest one of those parachute hammocks, small lightweight and you sleep like a rock. And a mosquito net too especially in a wooded area.
If you don't want to bring toilet paper get a package of baby wipes, thats for #2 and "showering" and cleaning if you need it. For a flashlight I'd recommend a crank or kinetic flashlight that basicly last forever and no batteries. Maybe a crank radio too. As for cellphones maybe a solar charger, small and cheap. Unless you plan to spend the rest of your days in the woods being able to call home, friends or relatives, or 911 is kinda big deal in an emergency situation.
And as cliche as it sounds, add a shemagh to your kit. I used one overseas and it really keeps your neck and face from being sunburned, can cut it up for TP, pillow, wrap up small clutter, makshift bandage, helps with skeeters or flys in your face, wash rag, keep your head warm, etc. It really is a do-all. Add a multi tool, spandex shorts, really you can wear them for days if you have to with no chaffing, they don't stain or wear thru so fast, dry quickly if you get wet, don't stretch or get ratty, and are a god send if you are somewhere hot and dry.
**Oh as for a long arm, I'd bring my AR, versatile rifle for hunting to SD, and I wouldn't be "afraid" of approaching law enforcement with it, just take out the mag, hands where they can see them and just explain your situation. I can and do own rifles I'd use regardless what others think. I don't assume every person with an AR or AK or FAL is a bandito or spook or BG just from what rifle they are carrying, I don't wear ponchos, gangsta clothing, or face paint camo. A cop or military isn't going to shoot you with out cause or questioning first I do not look like a thug nor would I be stupid enough to approach an LE with a loaded gun in my hand or creep up on him. If I approached someone out of uniform if I was forced to "bug out" I will damn well be the one armed and with the upper hand.