I have conceived a new space yacht using laboratory level thin film solar panels, the ELF-375 engine design, and allowing 100 tonnes for the balance of the spacecraft. I parameterized mast height and settled on 1500 meters. This configuration masses almost 500 tonnes fully fueled, giving a time to accelerate to the moon (8 km/s delta V) of 35.3 hours at high thrust.
Thin film solar http://www.nature.com/ncomms/journal/v3/n4/full/ncomms1772.html
Note that using 4.2 % efficiency and 4 grams per square meter for this thin film actually gives the power to mass ratio of 14.29 kW/kg instead of 10 kW/kg as given in the reference. With two 1500 meter masts and the resulting four 1500 meter booms, this thin film solar masses 18 tonnes and produces 257.3 megawatts.
ELF-375 engine http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA513936
The ELF-375 engine gives the highest electric engine thrust to weight ratio that I could find. The design point is 200kW giving high thrust of 95 mN/kW, (Isp ~ 1500 seconds), and high Isp of 5000 seconds at 35 mN/kW thrust. The engines are still quite massive at 64 tonnes for thrusters and 115 tonnes for the PPUs. The run to the moon, 35.3 hours at high thrust, used 196 tonnes of Xenon propellant and ended with tanks empty. The same run at high Isp took 80 hours, a propellant load of 51.7 tonnes and again ended with tanks empty.
Mast height http://yachtpals.com/largest-sailboat-4155
Note that the Mirabella V is 765 tonnes, 75.22 m long, with a 14.8 m beam and an 88.5 m mast. Look at the photos to see a really impressive luxury sailing yacht. The solar panels on my space yacht are configured somewhat like the sails on the Mirabella V, except that my space yacht has the second mast where the keel is on the Mirabella V and of course the deck is domed over air tight. Like the Mirabella V, my space yacht is for party cruises, but around the moon instead of the Caribbean.
Point 1 - The engines are far too massive. What can be expected by way of mass reduction, (thruster, PPU), if the engine design point was 20 or 50 megawatts instead of 200 kW?
Point 2 - Xenon propellant from Earth is a show stopper. Lifting 200 tonnes from Earth to LEO for each cruise is not going to happen.
In reading the referenced thin film solar cell paper I note that the reference is to solar cells and not to solar panels which the paper notes will require different design:
"For small, laboratory-scale devices the silver grid is unnecessary and detrimental to device performance, but it will doubtlessly be required for large-area devices."
I suspect this is a reference to the problem of collecting current from a large area. Am I correct in that the mass of the conductors required to collect and deliver this current to the engine system was not included in your mass estimate?
Resistojets using hydrogen could take advantage of the Oberth effect if the high specific power of the lab device is not too much reduced in a large scale device. A far smaller panel but more propellant mass for that alternative but if there is ISRU you might choose that for your yacht.