Armed guards inside, with full authorization to use force against any rioters who get in.

From what I recall, Reagan had plenty of detractors, but also many absolute fans. But both seemed generally more rational, and conversations of differing opinion more civil.

And your head didn't have opinions and information constantly pounded into it. The 24-hour news cycle was a brand new (and not as ubiquitous) thing during his presidency, Fox News didn't yet exist, and there was no internet. Did media outlets have left/right agendas? Sure. But it all seemed so much more...professional. If it wasn't all totally sincere, at least there was some sense of decorum. 

Were Reagan of the same age and demeanor as his first campaign, running this year, he would probably come off as too moderate for the modern Republican Party and have no chance of even being nominated.

And to think, he'd be about a decade younger (!) than our two current candidates.