how close is Chichen Itza to the hotel zone...going in April & want to chk it out..any recommendations on getting there from hotel?

Are you referring to the hotel zone in Cancun or where?

We've decided to stay a few nights in Valladolid, a little colonial town about 20 minutes from the ruins; there are shuttle buses available to get us to the ruins when they open.

Chichen Itza is a several hour drive thru lots of jungle and savanna. There are many bus tours, or you can rent a car.

There's a major highway, a toll road (~$20 each way?), from Cancun right to CI; the trip will take almost 2 hours. You could easily rent a car and do it.
Many many tour buses, but be wary of the ones that offer it for almost free (unless you like to spend your vacationhours doing time shares).
I think renting a car is a very good option; you could even do two days and stay on site (Hotel Archeologico is a classic) or very close for an overnight.

BTW, an overnight stay will enable a quick visit to Ek Balam on the way back (if you don't spend the entire morning at CI). Much smaller site, but a lovely setting and an incredible pyramid and different style; the plaster reliefs are totally different and truly amazing!

If you take a bus tour it's going to be an 8 hour day. They will pick you up from your hotel and take you to a cenote for swimming and to Valladolid for lunch before going to Chichen Itza. They will drop you back at your hotel at the end of the day. There are really several types of packages you can book depending on what you want to see.

http://www.cancun-discounts.com/chichen-itza.htm

I'm not of fan of driving in Mexico and finding things on my own. There is a risk in doing so. If you do go that route research carefully.

Risk? That's a bit alarmist. I've gone many times (once by bus, the rest by rental car), two lone middle-aged females twice, a couple times with DH, and once with the kids in tow, and never had a hint of trouble. Put a picnic cooler in the trunk, and bring lots of water and sunscreen. The bus is an ok way to do things, but a lot of time is wasted, and there are visits to tourist sites you might not like (for example, a cave, a cenote, a bad restaurant).
It's only 75 miles each way, a straight shot on a fairly new major highway, and a very developed site. The major sites in the Yucatan are pretty easy to find, actually!

I've been to the Yucatan Peninsula 9 times. And have another trip planned for later this year. Yes, there is a "risk" in driving in that area. I didn't say it was dangerous and to definitely not do it. I said if you do chose to go that way to research carefully. There are many posts about many unhappy tourists who get harrassed by the Mexican police. Then those people come back and report how terrible Mexico is, which is a shame. If they had just done the research more carefully they could have made a better decision. That is not "alarmist". That is cautious advise to someone that may not know otherwise.

I glad that you personally did not have any issues, but many people have had problems and to not provide the good and the bad regarding that issue is irresponsible posting. Give the OP all the information and then let them decide what is best for their situation. All I said was to research carefully.

I have rented a car in Cancun but have never left the immediate area in a rental car. I have an acquaintance, a professional colleague, who rented a car in Cancun about 5 yrs ago to drive to Chichen Itza. On the highway was a Mexican man whose car had broken down and he was standing next to his car on the road when he was hit by the car in front of my colleague's car. The driver who hit the man kept going. My colleague stopped to render help. The police came. The man died.

My colleague was arrested and charged w/running over the man and killing him. When he talked to the police, he told them the car in front of him did the hit and run, and that he stopped only to render aid. The police told him someone had to pay for this man's life and that if what he said was true that he should not have stopped! Evidence did not seem to matter. Colleague was in jail for over year before a Mexican lawyer finally was able to get him out.

Unfortunately these types of things really do happen. I guess he really should not have stopped.

KVR, you are absolutely right! One should read and explore all the information they can (good experiences and bad) and make their own judgments about their own personal comfort level. ("Risk" just seemed a little vague to me.)
We've always driven rentals in the Cancun-Tulum-Chichen Itza-Coba areas, and never had a problem. I've always read about the traffic-stop bribe issue, but never met anyone who encountered it. Of course, that doesn't mean everyone has the same experience. And, all travelers should probably have an active cell phone (Verizon will activate your US phone for Mexico; it's pretty easy.)