Would be a bit boring without time limit, imo. The map is the same as in normal game. If I want to further explore it, I can do it all the time. Ok, Survival has the low gear score, the cold etc, but I like the time limit. It is just more challenging with it. For me, the most annoying thing in Survial is the long waiting time in matchmaking and game finding. PVP Survival is almost "private" these days - the matchs often start with four players!
Not A fan of DayZ or State of Decay type games, and I have said before I just plain dislike Survival. Simple reasons why, it is a mini game, I do not find it relaxing, lack of cohesive main character carryover lowers my interest, and the skill nerfs have made combat so uninteresting to me. That aside, I have played it a few times to offer a few suggestions to most players new to the mode.
1st take time to investigate the normal map. remember to take note of important things like pharmacies, ambulances, CERA shelters, police stations, etc. These locations carry over to survival and are usually best for finding time extending Meds.
2nd Avoid checking your inventory after every single pickup, you are in a hurry, don't waste time. gather a bunch and just grab and go, or hold the equip button. deconstruct in the safe houses or while warming up by a fire
3rd Do not waste your time or resources trying to get skill power, the cool downs are awful, and the skills themselves are mostly worthless now. The only things that are useful are the pulse and heal skills. Firearms first and Stamina second.
4th Do not waste resources trying to craft full blue items or even all purple. You want to have as much as you can for gold gear in the DZ. Plus the required filters/flare gun/medkits.
5th most important weapon is a bolt action sniper followed by an AR.
6th Holster is the best single piece of gear, if you only have enough for one upgrade. Make a gold or purple holster.
7th Green and blue mods are better than no mods, but do try to hold out if you are comfortable
8th The DZ is confusing at times, but when in doubt find an alleyway along the edges. those dead ends usually offer the best guess locations for meds or DivTech.
9th Don't worry about the cache bags, the gear is mostly useless in the real game, Survival caches from the LMs are the best however.
10th Meds lose effectiveness, after about 90 minutes you will be lucky if they are still giving you a 30 second infection pause. By that point it is better to just stop looking for them.
As a general rule if you are over 2000 FA and 2000 STAM you are in a good position for the hunter. at around 3000 FA with an M44 you can one shot him.
Some other random stuff
-when throwing grenades shoot the enemies right before it lands... they get aggro and tend to not roll out of the blast.
-use the best weapons you get. even if you hate LMGs
-play during dead hours, you will have less players in the match and an easier time farming
-dead players are great sources of loot, but don't go across the map for them, if another player got there first the whole area is scavenged already and you just wasted time.
-USE COVER, and never let an enemy get behind you. keep moving backwards! or shoot through narrow alleys and draw them in
-other players will try to steal your gear drops. Either be prepared to rush in and grab items as the drop, or take time to make sure nobody is around
-most players tend to ignore the top of the map and it is a great source of gear.
-if it seems like you are only finding looted locations, pick a new location on the map and go there. don't waste your time trying to catch up to the other guy.
-odds are good that if a purple location is still up the surrounding loot most likely is too.
-Finally, if you get into a bad situation, don't think just run. you can try again from a better spot later.
Quick edit
I forgot to mention, avoid the area to the north of the construction site on the east side. there are so many invisible walls and glitches there it will just cost you time. It is also annoying AF to climb on boxes only to discover you can't hop off the dang things.
Same for the area around the Lincoln Tunnel Mission, those over passes really throw off way points and can drive you insane. So avoid it unless you are comfortable without using the map.