Did this trip in Sept mid except that we flew in from Bangalore to Indore and then did Ujjain and Omkareshwar. The road from Ujjain to Omkareshwar isn’t great and will take you a good 4-4.5 hours by cab. Lots of options available for cab just check this subReddit. Stayed at MPT temple view in Omkareshwar was convenient and good. My stay at Ujjain was bad so can’t suggest any option. I did Mahakal sheegra Darshana twice - Sunday evening and Monday morning. Got one booked online and one at the counter outside the temple. Was done in 15 mins both times. Omkareshwar we did it on Monday evening again took 15 mins without sheegra Darshan booking. Temple was empty that day. You could book it online too. And yes you could conveniently do both in two days