Leadership has already met about this topic- at least acc. to Breitbart. Answer is that all townhalls have screened attendees (for security, registered voter in the rep’s district ie. proof of ID just like voter ID, press credentials that are real and proper, and several other screening points to prevent non-relevant attendees and outside agitators). If they can’t provide proof they are in a reps’ district and a voter— they don’t get in- period. First level of screen is paper application to come to the event- weeks prior.
The best security would begin with what you suggest, but I would go much further. While it limits the number of venues for the event, the results will be much better for both the speakers and the audiences.
Start with underground or elevated parking adjacent to the venue, which allows for screening of vehicles, vehicle security when parked, and secondary screening from the parking area into the building.
The auditorium should be “three segments back” from entrances, say a lobby, a secondary room, and then the auditorium. This provides protection from both vehicular attack and noise.
Last, but not least, having a couple snipers on nearby rooftops is always good. They, and a few people with walkie-talkies to act as “pickets” to spot large mobs approaching, and you should be good to go.