After doing some more research, the selection seems to be quite solid, even inspired.
Evidently, there is evidence of strong support, not only from the Republican base, but from the Tea Party movement, as well, given the announced economic and budgetary postures. Tea Party supported candidates have shown great strengths, especially when run up against incumbents. That the Tea Party is still around, is somewhat surprising, given how political movements come along, have their fifteen minutes of fame or notoriety, and go. The strengths of the Tea Party in fact, could lead one to posit them becoming a third major party, but that should be a discussion for another thread.
Also, there was some polling done done in Wisconsin in July that posed the possibility of a Romney-Ryan ticket. "... Although Obama led Wisconsin by 6 points in a head-to-head matchup with Romney, the poll showed that the vote swung by five points in favor of Republicans when Ryan was added to the ticket. ... " and, "... A third factor, that has been mostly overlooked, is how Ryan could shift the youth vote in Wisconsin. PPP [Public Policy Polling] found that, with Ryan on the ticket, Republicans could actually win the 18-to-45 age group in Wisconsin over an Obama-Biden ticket...."
Paul Ryan's oratory and debate style have already led some to consider him the winner in a debate with a representative of the left, Rep. Barney Frank: "... A few months ago, I got to watch Paul Ryan debate entitlement reform with Rep. Barney Frank, who was rude and ill-informed. Ryan not only handled Frank gracefully, he won the argument. When everyone else's hair is on fire, Ryan keeps his cool. He's a happy warrior, reasonable and nonthreatening. ..."  Mary Cate Cary, "10 Reasons Paul Ryan Should Be Mitt Romney's VP Pick", US News.com
Recently widely publicised is the projection that payments made from Social Security to any given participant will now be less than that given participant paid in, and add in the vagaries and projected budgetary problems with Medicare within the context of Obamacare, Paul Ryan's message becomes all the more compelling.
Too, there has been widespread reportage of the fears (oddly enough, even from among the left, i.e., members of the Democratic Party) that chief among the reasons the country was heading in the wrong direction, was an increasingly larger more powerful centralized government.
Most vocal about this has been the senior age group, who grew up not having received the indoctrinations of globalism, see this as part of the increasing loss of individual and national sovereignty; Who also see Obama as part champion, part architect, and part product of this restructuring, and you are not likely to see them vote for him when presented with an All-American duo like Romney Ryan. So, I believe the assertion that Medicare recipients, especially when the explanation of the actual changes to be made to these entitlement programs, as opposed to the scare rhetoric from the Democrats, would not vote for the Repubs, is seriously flawed.
On the Catholic issue, all I was able to uncover was that the Church leadership, opposed the budgetary cuts, not the church laity. If anyone has any actual polling, I'd like to see some citation.