While both the 243 and 30-30 rounds are well capable of cleanly harvesting small to medium sized game, from a survival platform perspective the 30-30 has a better advantage. Here's a couple reasons why:

It is sensible to keep the profile of a survival carbine as small as practical. For this reason, the addition of a telescopic sight to the platform is undesirable. While adding such a sight to any rifle will improve the range at which the firearm can be used, it is not essential for survival style hunting. Since a 30-30 is intended for ranges where open sight systems are proven effective, the need for an extended sighting capability with this round is greatly diminished. In the open range, the 30-30 is not as effective due to it's lower velocity. Bullet drop greatly reduces the MPBR (maximum point blank range) of the load, requiring sight adjustment or compensation with limited reliability. Additionally, a telescopic sight will be more prone to shock failure in rugged conditions, making it even less reliable in a survival situation. The advantages of the 243 cartridge are essentially negated in a survival situation. So even though it is more powerful and has a much longer effective range, the ability to wield it to its full potential probably cannot be realized practically.

Except for heavy brush environments, the 243 (with an energy level much closer to 308 than 30-30) can do what the 30-30 can do within the same range. The difference in apparent recoil between the two rounds from a similar platform will be negligible, and shot placement using iron sights within the capabilities of the shooter will have likewise minimal variance on terminal ballistics. Because the 30-30 shoots a heavier, larger bullet, it would be a superior brush gun, and would tend to deflect less if encountering light obstructions in flight.

I believe the number of firearms suited to transit and survival applications are greater for the 30-30 than for the 243. However, I would still recommend a bolt action 7mm-08 in a scouting configuration as the superior firearm to either choice above.