There weren't really a horde of "Lincoln bodyguards" though. The Secret Service didn't even handle guarding politicians yet (They had just been created, but for their primary task of fighting counterfeiters). It's hard to imagine, but back then it was considered normal for politicians to just live like other people rather than being surrounded by bodyguards. You could even go as a normal citizen to the White House and ask to speak to the President (he might not have time to do so, but you could ask and people did)