Perhaps this clarifies things. Much like other states, there is criminal trespass and hunter trespass. Colorado is no different. Anytime you enter private property there may criminal trespass being committed - it's all in the eyes of the landowner. Pulling up to the house via vehicle on the driveway I can't imagine a case could be made for hunter trespass. Here is your two applicable Colorado sections - I highlighted the important text in RED:
Criminal Trespass(18-4-504)
1.A person commits the crime of third degree criminal trespass if such person unlawfully enters or remains in or upon premises of another.
2.Third degree criminal trespass is a class 1 petty offense, but:
(a) It is a class 3 misdemeanor if the premises have been classified by the county assessor for the county in which the land is situated as agricultural land pursuant to section 39-1-102 (1.6), C.R.S.; and
(b) It is a class 5 felony if the person trespasses on premises so classified as agricultural land with the intent to commit a felony thereon.
Hunter Trespass(33-6-116)
Hunting, trapping, or fishing on private property - posting public lands.
(1) It is unlawful for any person to enter upon privately owned land or lands under the control of the state board of land commissioners to hunt or take any wildlife by hunting, trapping, or fishing without first obtaining permission from the owner or person in possession of such land.
(2) It is unlawful for any person to post, sign, or indicate that any public lands within this state, not held under an exclusive control lease, are privately owned lands.
(3) Any person who violates this section is guilty of a misdemeanor and, upon conviction thereof, shall be punished by a fine of one hundred dollars and an assessment of twenty license suspension points.