Personally, I'd prefer if it was possible, through scavenging or replicating for a player to stay alive indefinitely, but whatever replicator wizardry this would require shouldn't come into play until past the point that the player could have feasibly won the game through one ending or another, anyway.
Indefinite play should be possible regardless of anything else, and without the need for any replication at all.
The minimum (non-respawning) tech needed to have the possibility to create any item would be:
1 Light Diode; 1 Pulse Beacon; 1 Particle Accelerator; 1 Battery; 1 Fuel Cell; 1 Energy Coupling; 1 Warp Coil; 1 Solar Panel; 1 Field Emitter; 1 Storage Container; 1 Glass Tube; 2 Scrap Metal; 2 Computer Units; 1 Tzo Crystal; 1 Empty Container; 1 Gravity Device, 1 Lighter, 1 Pistol Chassis, 1 Demagnetiser.
This isn't to say you'd be able to make everything at once, but really - that's not a lot of stuff. Energy is recoupable (even the Android should be able to run at a surplus once he gets an operational power supply and ether generator/biomass decompositor), batteries and scrap are recoupable, ether is recoupable, tzo crystals are recoupable, and bullets are recoupable, this is my current issue with Replication:
The hard to find tech: Particle Accelerators, Field Emitters, Solar Panels, Fuel Cells, Energy Couplings, Demagnetisers, Storage Containers, Glass Tubes, Warp Coils, Gravity Devices, Pistol Chassis', Empty Containers and Pulse Beacons, Light Diodes.
Particle Accelerators - You'd need four or so for the escape ending, twenty-six to have literally one of every gun, and let's say that there are personal tech items I've forgot and add five. - This is only thirty-five.
Light Diode - You only need five.
Solar Panels - Three and I'n pushing it.
Fuel Cells - If you have a 1/100 chance of a stun laser marine dropping a stun laser, then you'd actually get an unlimitted number of these anyway.
Warp Coils - Three, if you want a Warp Gun, a Warp Drill, and a ticket home.
Gravity Devices - Again, four or so for escape, two for other uses, maybe ten total on the outside?
Pulse Beacon - Four. Tops.
Field Emitter - If you wanted extra, permanent, stasis field bases in five maps you'd need ten tops.
Demagnetisers - Twenty-two. The two are for the gun and making infinite batteries out of scrap metal.
None of these complicated devices is easily replicated, but really, for those you can't easily find elsewhere - Why do you need more? You can already survive indefinitely. The only things that would be possible to replicate in a sensible fashion would be:
Pebbles, Scrap Metal, Computer Units (maybe), Bullets, Food, Glass (tubing/container), Pistol Chassis, possibly Energy Couplings, and water. On the outside, maybe Motion Detectors and Medikits.
This allows: Infinite Batteries, infinite pistols, infinite bullets, infinite food, infinite empty containers storing your infinite water, infinite pistol turrets, and infinite health - provided you could gather appropriate raw materials to manufacture them.
If it's too complicated to replicate normally, and can't be looted from your enemies, the biggest probability is that it just isn't necessary to have that many.
If you will add the ability to chop down trees for wood, will the trees grow back over time? If not, do you have plans to add some kind of permanent placeable technological light source, that coupled with a stasis field and some kind of ether burning cooking surface, would allow you to outgrow the use of fires for heat, light, and cooking?
Certain trees, and certain trees only, would be instantly destroyable for wood. Whilst there will be a low % chance of them spawning/respawning, this will only happen in spring. Doing so will also remove the long term benefits of the tree - namely fruit, which will drop once every few days.
Permanent light source - Possibly, only the human right now needs a light source outside of special cases (indoor areas only, where turrets/vehicles/night vision wouldn't be useable). I may attribute a light to the Ether Burner (the aforerequested heat source/cooking tool which is planned, but not implemented), or the Ether Generator (burning fossil fuels to power your bases, huzzah). Ether will be either directly "growable" from a biofuel manufacturer, or gatherable from other sources (well, it will technically be both, but good luck doing that simultaneously?).
The Stasis Field is present in 0.25, and later versions will have actual shelters you can enter into to rest, dropping your deterioration and helping you heal without technological involvement (and with the protection that your enemies must kill it to reach you, unlike a stasis field).
However like all your structures, these will be vulnerable to destruction by rampaging aliens, and deactivatable at your leisure (though reactivating them each time will take some energy); so before you start up a large permanent base encampment you may want some turrets or the like to defend it.