She would confirm her late husband’s peace treaty with Prussia and make Prussia an ally. By the end of the 7YW Prussia was exhausted enough not to be a potential menace Elizabeth was afraid of. A complete defeat of Prussia was not in the Russian interests because it was going to make Austria too powerful and prone to the interference into the PLC affairs. The same goes for its possible meddling on the Danube, which could conflict with the Russian plans.
Franco-Austrian Alliance was not a problem as long as both Russia and Austria had common interests against the Ottomans and, at least as long as MT is in charge, one can expect it to be a quite unreliable neighbor always trying to limit Russian expansion and to get something for nothing. Anyway, it would not represent a direct danger, especially with Prussia being on the Russian side.
Elsewhere,
if Catherine overthrown Peter (there was a brief window of an opportunity when the field army was concentrating on the Russian border for a future war with Denmark and the Guards were still in St-Petersburg unhappy with a perspective to leave the capital; the opportunity was gone after they were replaced with the regiments returning from the 7YW) then she finds herself in a need to start generously rewarding the main plotters by giving them state peasants as serfs by the tens of thousands, promoting into the high positions for which most of them did not qualify, and throwing money around as if the Treasury was not empty. Peter did not have any obligations of the kind so under his rule the serfdom never got to the extremes both in the numbers and severity. On a contrary, using the credit he got by his Freedom of Nobility act, he passed through some restrictions on the serf owners.
Also, as a part of her campaign for gaining the popularity, Catherine would be forced to further relax discipline not only of the Guards but in the army as well, which should have a negative impact on the future war. The same goes or abandoning Peter’s attempt to enforce some competence among the “honorary generals” (aristocrats who were getting the high ranks without bothering to serve and potentially could claim commanding positions in the case of war). Of course, Peter’s way of doing this by forcing them to learn a parade ground drill could be criticized but at least they were learning what was considered at the time an important part of a military training.
What else? Most probably Catherine would create State Bank, an idea floated by Peter before the failed coup: with the shortage of gold and silver, Russian government had to introduce a paper currency sooner rather than later.
It is also probable that, with some of her supporters getting the high positions in the army, the pretty much inevitable Ottoman war would be conducted not in the most efficient manner until the circumstances are forcing her to put Rumiantsev (who was an outspoken Peter’s loyalist) in charge.
Now, as was demonstrated, some of the plotters eventually pardoned by Peter proved to be useful people capable of performing the important services. Take two major figures:
Allexei Orlov, by producing Russian own breed of the cavalry horses, provided solution of one of the serious problems plaguing Russian cavalry: even during the 7YW the native horses were too small which put Russian cavalry at a disadvantage. While the problem was not completely resolved during Orlov’s life, enough of the bigger horses was produced to satisfy a need of the heavy cavalry.
Gregory Potemkin - proved to be a good military and civic administrator (when kept under strict control
); he got a lot of credit for building up infrastructure of the former Crimean territories.
