I'm 77h in after like 3 weeks. Yikes. I think MP will be an utter blast. Just about managed to 'get it' and get a farm and generator up and running now and have survived 2 months on builder. My tips for newbies would be:
Use the mouse option for 'walk to' then speed up the time to get places 'fast' without using up cardiomana.
Only fight when you're well rested and fed, else powerwalk away.
Zombles use line of sight and amble to where they last seen you, then look around for you. They only 'look' for you at certain times within this (e.g. not when climbing? so i've noticed jumping fences a couple times in quick succession helps. Or getting out of sight behind a building and smashing a window, then running way - they all think you're in the building and swarm that instead of chasing you.
You can hit V in cars to bring up a context menu that lets you sleep in cars.
Get a car and use the horn (Q) to draw hordes away from your base.
Car keys can be on the ground around a car, or in the gloveboxes, or on the seats.
Shout to check if rooms / buildings are empty (Q) before opening doors.
Eating the same meals all the time gets you depressed.
You can 'forage' for sticks that let you make spears if you can't find a weapon I had to google how to use the search thing.
Only use guns as a last resort. Or to draw hordes away.