2 rs, 4 mex, power, rs, power, rs, power, rs power, walk ACU forward, capture his factory, put up PD/AA like you did if needed.
He would still have had those couple of cruisers but they take a while to destroy RS, especially if you can manage to keep your engies there to heal, and hidden behind said RS so the cruiser's missles can't hit it.
I don't know for certain, was just trying to make a suggestion, but if I had to guess, if you put movement speed on your ACU ASAP you could be capping his naval fac before his cruisers were in radar range of your base.
The only sonar he had (I think) would have been on the cruisers so he may not have seen you coming until too late. Even if he puts up PD its only 8 more points to teleport after movement (you should have this at like 4:30 I think), so you can circumvent his defenses to destroy his economy (and if you can range your PD properly, you can teleport behind and destroy his PD using superior range). If there is any areas that have less then 2 PDs, start capturing stuff (one PD will not kill you fast enough, especially if you heal with nanites).
Like I said I do not know for certain if it would work, but against that specific build I _think_ it would do well.
Assuming the acu does get to shore your not going to have a great deal of resourses to abuse pd, and the crusiers with just kill your engineers and rs without much resistance. So then your trapped with no resourses with just an acu.
