Nov, Dec & Jan are the optimal time of the year where it's the coolest and least amount of rain. However, it's still very humid so if that's a problem for you folks, something to consider. Aside from buying a motorbike, comments made are well advised but one thing not mentioned is the 'liability factor' of driving on your own, if you get into an accident, it will most likely be your fault even if it's not because they will pay people to testify that it was. So in addition to any medical costs, there are additional payouts you will be fined if determined the accident was your fault. It's just not in Cambodia but in general, SEA as a whole. Booking private tour groups to see various places where accommodations are included is safer and more comfortable. Thru the travel agency, they can recommend car rentals with an english speaking driver to see places not covered by tour. There are also individuals you can hire for local tours as well. However, this is the most expensive way to go but the experience and comfort in traveling around will be best remembered. I say this because you are at retirement age and if you were much younger, the adventures of 'roughing it out' would be easier to handle. You can see a lot in 3 mos so the offset of saving 3 mos of expenses to travel 1st class would be an offset to what you expect to spend. Also, to avoid waiting in long lines to get your visa, having it in advance and then extending it before it expires which I did saved me a lot of time which took me around 20 mins to pass customs and immigration processing. Also, if you travel light, it allows you room to bring back souvenirs too. Many places offer same day service to wash and iron your clothes and the cost is not that expensive compared to what you would pay in your country. If you love seafood, Kep is worth visiting for the food alone about 1 hr drive from Kampot which is a larger town that offers nightly riverboat cruises where you can have dinner and hopefully see fireflies. They also have the best local tasting beef since it's mostly muslims that live there, few places offer pork dishes plus most of the vegetables are locally grown and known for it's famous "Kampot Peppers" as being the best tasting in the world. I lived here for 3 yrs in 4 different cities and what I know now, this is how I would travel and see different areas of Cambodia. I'm retired as well and tried it the other ways trying to save money but the hassle and headaches I went thru, I regret taking that option. Places I still want to see so what I recommended, I plan to do the same myself since I plan to go back to America near the end of this year. Regardless of what option or ways you take, I wish you folks a happy and memorable vacation and safe travels.