Domestic connections over 4 hours are not allowed on a single fare (doesn't matter if it is last flight in or not) in vast majority of cases (including this one). When you are booking an overnight connection on a single revenue ticket, you are actually booking two separate fares together. The fares have to allow end-on-end fare combinations (some cheaper revenue fares do not other than with A-B-A routing, aka a roundtrip). The booking search will up-fare you to the cheapest fares that allow it. However, there are no award fares on these routes that allow such end-on-end combinations (they all require A-B-A routing) so there's no way to book two fares on one ticket for the route. This is why the award search bombs out when you try to do a multi-city search for this route. You'll need to book two awards on separate tickets.

From the award fare rules --
END- ON-END MUST BE AN A-B-A COMBINATION. SIDE TRIPS NOT PERMITTED.