Both ways work but...
On 50 you have Monarch pass which isn't terrible but it is a long slog up and down and then on 285 you have Kenosha pass which is much less so than Monarch. However it is for the most part 2 lane then hit I470 and take it up to I70, I76 then hit I25. (or if you have time and inclination you could take a back way up to Loveland and hit 25 there)
Taking 50 all the way to Penrose and catch 115 up to the Springs and I25, 50 follows the river once you get to Salida and is a bit slower good road but just slower 115 is good road. You will hit Springs traffic and Denver traffic going that way which is total **** and be aware there is a section of I25 between Monument and Castle Rock that is under construction for about 20ish miles that is very narrow and traffic is very problematic through it now and for a while yet to come.
Personally I would go the 285 route to avoid the Springs traffic and 1/2 of the Denver traffic even though it does have the addition of Kenosha pass but it is a short one.