The Hard or "Red" Missions on Beatnik Bandits. I am certainly not the coder and also certainly not the most effective fighter or tactician, but I have died and succeeded enough times to feel warranted in listing some points to be cognizant of when offending these missions.
These are not designed to be attempted alone. However, one with unlimited free time and no concern for riding their bicycle more than they engage the mission can get it done.
You may as well participate expecting to be killed. If you go in thinking this, you will be prepared in several ways.
First, you won't carry anything more than you need: expendable primary and secondary weapons (with roughly 3 rounds per enemy present), extra bandages, painkillers, and morphine, and food and drink. A GPS to scan with is also invaluable if you have a spare. It is not uncommon to be unable to relocate your corpse and these missions have an uncanny ability to create them. Keys to things you didn't drive there are not worth losing.
Second, you're probably going to die. Being mentally prepared for that makes it far easier to swallow when some good-for-nothing Bandit flanks 400m and shoots you in the back. Being ready for a long ride makes Rage Quitting that much less appetizing. Hold Shift while you pedal.
Third, if you're expecting to be back at the coast, you can coordinate rides or even stash a cheap car in Cherno with an extra primary and ammo.
These missions are dynamic. They all require a different approach (multi-distance engagement, Close Quarter Battle exclusively, etc) and participating in them is the only way to learn the best approach to each and what suite of weapons you'll need. For example, Green Mountain has a rock outcrop that is so easily defensible that a single player can often hold it with no assistance and only a red dot or iron-sight weapon. You'll be right in the belly of the beast, but once you're there you're hard to dislodge.
The terrain is NOT their advantage. I know that looks like a mistake, but I assure you it is not. The AI will out-maneuver a player most easily when the player does not consider the map and it's flora. The high ground is not always your friend and pine trees will get you killed. Make them come to you and keep sight lines on the (hopefully) limited routes you. They're on a hill with a castle? So what? You're in a valley with enormous oak trees blocking their bullets and sight lines straight to their only flankable avenues. Keep that head on the swivel.
Numbers ARE their advantage. You are going to engage 30-40 Bandits who don't need to shoot twice if they see your head. Don't worry about your kill count--shoot them until they stop running toward you and check your GPS scan. Remember, all PC's (including you), bandits, and traders count toward the total on scan. Vehicle occupants (including M2 gunners) will not show up. 4 extra bodies come up on the next scan? Congrats, you've just inherited a UAZ crew who is likely carrying only Lapuas.
Size actually does matter. Shoot them with something holding 7.62mm (DMR, FAL, LMG's) or similar ammo. Yes, it's more expensive and rarer than NATO 5.56mm, but you'll get it all back when you loot their bodies and you never want to shoot a bandit more than once to drop him. Broken legs just mean a harder enemy to see at distance. They can still see you.
They're smart, but they aren't wise. When you inevitably die from a bullet traveling straight through a wall or tree into your head from 600m away and bike back, they will probably have returned to the center of the Mission. I have no doubt that Rupert can and will change settings to make this advice useless, but for the time being they will not be hanging around the place they last killed you. Be cautious, but be confident.
Are you alone? If not, don't be greedy. No one takes a thing concerning loot without announcing it and you should wait for everyone to review what's present before you take something. We all suck equally, be generous.
EDIT: Bloody mentioned an excellent Looting Method below where all loot is loaded up "Beverly Hillbillies" style and sold en masse, then divided. Good call!
This was meant to list vague best practices and is in no way comprehensive. Please feel free to list other rules below and know that I'm making another thread for favorite weapons, specific maneuvers, and other non-general ideas. I'll likely edit this, so go ahead and comment!