Mandatory voting would certainly solve the problem. Of course, generally, public opinion doesn't favour it, so I think it's a lost cause to be promoting it in our case.
Australia votes on Saturdays, and of course when they have the mandatory voting it's difficult to disentangle the voting. But I've certainly heard the chief electoral officer of Australia talk about how they get at least half the vote before noon on Saturdays, when people are out doing their marketing or whatever. If there are objections to Sundays, you could consider a Saturday solution. Of course, that wouldn't butt up against a Monday election, but Friday-Saturday would work.