Realistically, if you are accepted to DS and you shadowed dental work, you should have some free time. Unfortunately there are many days you won't.
I went to DS in the mid to late 90's and I'll try to make it as relevant today as possible. There are 3 legs of work in DS...1) Class work in basic sciences and dental concepts, Basic sciences in DS were nothing like in undergrad and twice as intense. 2) lab/preclinic work. We had to our own lab work except ceramics and processing dentures and partial framework. 3) Patient care. We get 3 hrs to work on pts. Unfortunately I was slow in all 3 legs. If you want to specialize, you must have good class standing like top 10%. Of course DSs are different, but since they need to be accredited, they are all equally rigorous.
To get an idea what school work is like, my first year was mainly class work and some preclinic (not working on live pts). We had a lab technician classmate who aced all the preclinic lab...he could do it in his sleep. We had a mechanical engineer who aced all the books with little studying. He was also quick with lab. The sooner you finish lab work, the earlier you go home. Usually in the first year, the faculty will know who the top 10% will be. A lot of work are subjective and they will give the top more leniency. 2nd year was really intense with books. We get finals every 3 weeks. We started doing fillings on pts and I couldn't get my first pt numb for a lower filling. 3rd year was intense with all 3 legs. 4th yr had little book work (mostly electives) and more clinic time to complete graduation requirements. We had to cement 4 bridges (I had to do 5 because my 4th skipped town with a temp bridge), 4 partial dentures, 4 complete dentures, about 30 to 35 crown units (including bridge units), ~80 to 100 class 2 & 3 fillings, 28 RCT canals, Pedos with pulps and SSCs, 8 quads of perio SRP. We had to do phased work like articulated study models, perio first, then fillings & RCT, then crowns, then partials, etc so many times you have to do extra work to get to the crown or partials stage. It was the worst 4 yrs and I still have nightmares.
My sister graduated 11 yrs after and she only had to do 1/3 of the pt requirements. She said many weren't able to complete requirements because there weren't enough pts. I always tell pts who cannot afford a crown or other work to go to the DS. I'm not sure what DS graduation requirements are now.