I am guessing that there are two wasps involved primarily. One is the European paper wasp, and it makes small nests of paper (ground up wood fibers) in under eaves or in small cavities in all sorts of sites. It particularly likes to attach the nests to weathered metal (e.g., farm equipment. A sheet on this is at: https://extension.colostate.edu/docs/pubs/insect/05611.pdf

The other is the black-and-yellow mud dauber. This makes mud nests, usually located under eaves on wood surfaces.  A sheet on this is at:  https://webdoc.agsci.colostate.edu/bspm/arthropodsofcolorado/Black-and-Yellow-Mud-Dauber.pdf

Both would be spending the winter on or near the property.  The paper wasps survive winter in the adult stage hiding where ever they can find some cover.  (A barn would have lots of areas that provide that).  Mud daubers survive winter as a partially grown insect within the cell of the mud nest produced the previous year.

Paper wasps feed on lots and lots of insects, particularly caterpillars.  Mud daubers hunt spiders.

Why did you see more last year?  It could just have been a great year - insect populations go up and down for reasons rarely understood, but normally if there is a very high year, things settle down the next year.

However, it is possible that, if the problem is European paper wasp, it may be fairly new to you.  This is an insect that was first recorded in eastern Colorado in 2003.  It is now very, very common along much of the Front Range and has been for over a decade.  But perhaps it took a little longer to get to Peyton and is a fairly recent arrival. 

What to do is the problem here.  No good traps or any magic solutions.  The best I can offer is to spot spray sites where you do not want these to nest.  Several common over-the-counter insecticides would work for this spot spray - pyrethroid insecticides that will kill on contact for weeks after application, with active ingredients such as bifenthrin, deltamethrin, cyfluthrin, cypermethrin, or cyhalothrin.  If it is paper wasps then it is not to early to do this - they are already out and usually start nesting in April.  Mud daubers come out later, more of a June/July issue.