I also only had one rifle for a time, at age 10, a Marlin 25 Santa brought me, since then I have been Blessed enough to keep a well stocked safe.
But If I had to choose one , the Ruger 7x57 I have would cover me perfectly fine. PDs to elk.
But the wife would need a gun so I would have to keep the .300 ( for me to carry) , and the goats tend to be wary here, so my .260 Is a necessary item( custom built long range set up) and the .243 is also needed so on and on it goes........