First do not waste your time to book in advance there are always more seats available than travelers.
And as you know, as you should know, on Hispaniola, if you book you will be the only one who believes it's booked.
The bus leaves Santo Do. at 9 to Santiago. ( I mention it to explain that your bus is coming from La capitale)
Then at 12 Santiago to O'Kap (Cabo Haitiano)
If not a big mess at the border you should be at 16 (4PM) OKap.
Fare: US$20 or equivalent Pesos.
Pro : a charming bus stewardess will take care of your passport formalities at customs.
Con: If DR/Haiti relationships under high pressure they will put their energy to make this bus late.
Other option:
Take Expreso Frontera (La fria) every 20 mn at Santiago to Dajabon Pesos 400.
Cross the border.
Take a comfortable moto concho right after the bridge to bus station. Pesos 25.
Every 15 mn a bus to Okap , (comfortable) Pesos 100. (yes you can pay Pesos)
One hour after you are downtown Cap Haitian.
Pro: you can leave earlier Santiago than noon. So you do not arrive at 4 PM or later.
Have in mind Banks and lots of business closed at 3.
Con: At the border it's "do it yourself" formalities but always it's much faster.
Cordially
P.
