I fear that once the war started, winning is the only option, unless a peace is brokered which returns the complete status quo. Now that would have been reasonable, but WW1 wasn't started or led by reasonable people.
A separate peace would most probably not be victorious and even with pre-war borders would still entail losing the Balkan-influence.
I assume you mean status quo pre-war. I can't see this option. It was not two alliance systems dominated by two superpowers, but instead two alliance of Great Powers. So in some ways you have 3 CP powers and 5+ Entente powers all negotiating a peace deal that will have to be done very fast. The problems with Prewar status quo.
1) France wants A-L.
2) Japan will not give back its gains unless it believes the UK will go to war over it.
3) The UK dominions will not want to give up its gains.
4) The Russians want Poland back. At times they hold part of A-H, so this maybe doable depending on what date the peace offer is made.
5) Reparations will be an issue.
Quite Frankly, I can't see the Entente even agreeing to unified negotiating position to make peace offer. The Entente could probably live with status quo prewar in Europe plus German reparations plus some German naval restrictions plus keeping the colonies captured. The problem is that in a negotiation, you have to give something to get something. The only issue I see as workable is the reparations. Germany could probably agree to excessively large payments to Belgium and France if Germany got the Belgium Congo. I don't see how to get around the German colonies taken.
So now we have to move for status quo prewar to status quo date of negotiations. And once we do this, then we have to give Germany something for evacuating France. (Germany thinks it is winning at this time). Germany can probably accept a "independent" to client state Poland. And since most of the time, Germany was fighting on enemy soil, we have moved from Entente win terms to CP win terms.
And I see the same problem if German extended its interpretation of "status quo" prewar. It would ask for all its colonies back, for Serbia to be puppet of A-H, prewar French/German borders, removal Belgian forts on German borders. Now I could sort of see German offering Russia its prewar borders in the east as a way to try to split the Entente. But this offer is shot down on a couple of reasons. France will not sign on Reparations and A-L issues. UK will not like the forts term. And its dominions + Japan will not want to give back colonies. Japan in particular will want some British Colony or other equivalent concession for giving back Tsingtao, and for the life of me, I don't see what the UK can offer Japan.