Well, first off... bugging out shouldn't be Plan A, it should always be B or C. Okay, first you need to get the funds together to get at least one long gun. To keep this simple you can get a PCC(pistol caliber carbine) like the Kel-Tec Sub 2000 or Hi-point Carbine. If you have Glocks, Kel-Tec accepts those mags... the Hi-Point only takes Hi-Point mags. Having a PCC will reduce the amount of ammo you'll have to carry, as well as the number of different calibers. Simple is always better, right? However, if you do want a traditional carbine of a different caliber there's always the M4, of which you're very familiar with. AKs are always an option, the under-folders a nice(My choice is a Polish AKM under-folder). My wife's choice is an M1 Carbine, it's light, accurate, has good firepower and is effective out to 200yds. I recommend that both your wife and you have tactical chest rigs, I also like drop-down thigh holsters. Level IIA vests fit nicely under these and provide some defense against pistol calibers. Your vests should have IFAKs on the as well, a small pouch of fire starting material is a must and water purification tabs. Naturally, don't forget some sort of water pouch. Mil-surplus canteens work.
Having a map, both road and topical is handy to have... along with a compass. Walkie-Talkies are nice to have as well in case you become seperated, you can communicate. This all needs to be in your vest/chest rig. Okay, on to spare mags... I have six 30rd AK mags on my rig, and three spare M9 mags. My wife's rig has six M1 30rd mags and two M9 mags. I also have a Kel-Tec SU-16B folded and attached to my pack, along with five 20rd AR mags in the pack. My wife's pack has a pouch of four, 30rd AR mags. This spare long gun is a just-in-case measure... you never know what might happen. It does add extra weight of course, but it works for us. Now, onto the other contents of your pack... this should differ slightly from person to person. Naturally, you need more water. Don't care how you store it, but you need more... like another liter in each pack. You have two people, spread the weight out. Know though, two people plus an infant means you'll need more than others. Plan accordingly, I suggest you make room for at least a gallon each... that babies going to need formula. On to that, I'd suggest that you get some of the travel packs of formula. Diapers, you'll need diapers!!! Pack some disposable and cloth ones, you may find a water source to wash the cloth ones... if not, make due. Infant Tylenol, anti-gas medicine, diaper rash cream and whatever else you think your child may need! If you're living in the wild and humping it... your baby will get upset.
You'll need a way to carry the child long distance. I don't recommend the chest things! One, that's were your mags go and two, if you're taking fire the child needs to be protected and away from YOU... the target. I'd suggest those off-road strollers with the big tires. If you can afford it, get extra Kevlar to line the stroller... and ensure it's a green, brown, black or mix of those colors. That'll need blankets and insulation for the baby, you can get cold and wet... NOT the baby. Another thing to think about, is if you open up putting rounds down range... that's going to be extremely loud to an infant! AVOID CONFRONTATION AT ALL COSTS!!! If you fear you'll have to open up, tell your wife to displace and you'll cover the rear. Get the baby away from the shooting if you have to shoot. If you can't, you'd better hit what you're aiming at in short order... you don't need a long firefight. If you're ambushed, volume of fire wins meeting engagements! Consume your target with lead, unrelenting, uncompromising firepower! Don't worry about conserving ammo, just take the dead guy's stuff after you kill him/them.
You'll need food, I recommend the MRE side items. They're small, light weight and don't require your water to eat, are packed with calories and are water tight. Don't pack too much food, water is more vital and if you have to... you can eat leaves, bark, small game, berries or whatever else. Pack vitimans to ensure you're both getting enough, as well as fiber pills! You aint gonna be sh!ttin' right no matter what, but those will help. Another first-aid kit in each bag is a must, anti-biotics, burn cream, anti-itch, insect repellant, Tylenol, Asprin, foot powder, baby powder, dry soap, tooth paste, @ss wipe, anti-diarrhea, TUMS... and so on. Obviously, the travel sizes are a must. An emergency tent, emergency blankets, mosquito net, para-cord, rope, extra knives, extra fire starting equipment, fishing line, hatchet, zip-lock bags, flash lights, extra batteries, small bottle of motor oil(firearms lube), small cleaning kits, extra D-hooks, ponchos, light sticks, junk silver & .22lr(potential barter items), extra socks and underwear(change often, ring-out & dry dirty ones), and a sh!t load of knowledge and ingenuity!
I could add more but, this should give you an idea.
