Over 14 years, I towed three different lite fifth wheels with two different true 1/2 ton trucks. I have no complaints about my towing experience. Yes, these rigs were slow on steep grades, but never inadequate, really not much different than any other RV.
Now, none of my fifth wheels weighed 10k lbs, but again neither of the trucks compared to today's 1/2 ton offerings in terms of capabilities. So, w/o getting into the fine details you can probably put together a combo that will work.
But, I will also recommend a 3/4 ton truck because as newbie's you are likely to decide very quickly than a 'half ton towable' fiver is not what you really want for retirement RVing.