J a s,
you don't need a fancy aviation all singing and dancing GPS, I use an old Garmin 12XL, they are dead cheap on ebay. Just put the lat/long of your waypoint in and every now and again make sure the arrow is pointing someway forwards.
If you don't want to (or cannot with a loaded and tired 180HP) go up to 10,500 in the narrow corridors then you can still fly over the canyon to the west of GCN. David Viewing put up a good map, if you look at the blue routes from GCN those will take you to/from vegas and you will avoid the 14000ft areas. There is a VOR at GCN so just tune it up and fly the 270 radial (approx).
Grand Canyon was absolutely brass-monkey freezing recently, DA would not be a problem, but wind was strong and ceilings were very low and there was ice and snow around. Keeps the tourists away, rooms at the rim were dirt cheap and available on the day. It's a very beautiful place when the snow is 2 feet deep on the rim, in six months time you will be in shorts and T-shirts and drinking litres of fluid to keep hydrated.
Flying into LAS at night is great, they will vector you in so your final approach parallels the strip, make sure you do it at night. However if you are worried about flying to catalena in a SEP you will not like flying over the canyon and desert at night. If you lose your engine you are in a lot of trouble, though if it's a full moon you will be able to see enough to know what you are going to hit, but not quite well enough to know whether it's a nice surface until it's too late.
If you need any charts PM me and I'll post some, I have lots of old ones around but nothing much has changed, buy current ones when you get there.