Jacky
 

I’ll be visiting Glacier National Park in late June 2020 and want to take a tour on the Going to the Sun Road. My question is several parts: (1) which tour operator is recommend - Red Bus Tours or Blackfoot Tours (2) which tour is the best..i.e.... 4 hr, 8 hr etc (3) which side of the park is the best to originate from - East or West side.

Is this a solo trip as you indicate (I'll)? Where are you originating from? I think that Red Bus Tours has a much longer history and reputation. I don't know where they pick up passengers.
My favorite lodging in the area is at Meadow Lake Resort in Columbia Falls MT.
Depending on where you are coming from, flying to Seattle, Portland or Spokane might make sense and taking the Amtrak Empire Builder overnight to Whitefish. Renting a car in Whitefish is my preferred way to go into Glacier NP. That way you can spend more time and take a hike if you want to.
I don't understand your title "Jacky".

Thanks so much for the information and bringing the title to my attention. I think I put my name there by accident!

If you are indeed traveling solo, you might want to take the train to West Glacier where you can catch a shuttle up to the Lake McDonald Lodge. The Red buses pick up at the lodge to go over the GTTS road.
About 100 yards SW of the lodge, along the lake shore is the spot where Ansel Adams took one of his great photographs.
Where are you coming from Jacky?