I have not hunted Wyoming yet, but did draw an elk tag this year.
I've been researching for a very, very, long time.
The units you mentioned are great elk units. Some of the best places to hunt elk in Wyoming according to what I've found.
But,56 is tuff to draw for a non-resident, almost impossible actually. There are only 10 tags total given out there a year.
If you're looking for a bow hunt only, a type-9 archery only tag might be what you want. But unit 56 doesn't have a type-9 tag, so you would have to draw with all the rifle hunters and then purchase a archery license to bow hunt it.
It is about 40% wilderness, so there is ample land to hunt without a guide.
Unit 59 does have a type-9 tag and can usually be drawn more easily than the rifle tag.
But, lots of wilderness there. About 75%, so a guide would be an extra likely need to find elk.
Very rugged terrain also in 59.
How many points do you plan on having in 2018?
I may be able to suggest a couple other units to look at.