I'm leaving on Thursday before my mail comes and will be gone until Sunday evening.  Usually, my parents pick my mail up each day when my DH and I are gone.  Before PBS, we mainly got junk mail so if they missed a day or two, it wasn't a big deal.  Should I have the PO hold my mail since I will potentially have books waiting on me.  I'm thinking I should especially since we've been getting lots of snow.  I live in town so my box is on the side of my house and not very big.  Most of my packages end on the porch below the box.  Should I PM the people who have sent me books to let them know that I will be away, but that I will mark books received while I'm gone when I get my mail on Monday??

I wouldn't bother PMing people about marking received when you get home since you're going to be gone for such a short time.

I would either arrange for someone to come and pick up your mail for those 3 days or, if you can't do that, go and put a hold on your mail for those 3 days.  That way, you don't have any books potentially getting buried by a snowfall while you're gone.

What I did when we left town for 4 days was put a cooler on my porch and taped a note asking the mail carrier to leave mail overflow there. We had someone picking up the mail, but just in case they missed a day, or the weather was bad, there was a protected area for the mail to go. It was easier than a hold on the mail for me.

you can also place a vacation hold on your account as well

you can put your mail on hold on USPS.com or by calling 1-800-ask-usps