I do not count on RA to have a fleet because, as Hack78 said, you WILL get owned if your opponent realizes you do not have a fleet. My approach is slower but in my opinion has a higher chance of succes.
I use what you would call guerrilla tactics to destroy assets a normal player would overlook, such as construction ships. structures not yet built and the like. I guarantee he will be absolutely pissed, will subestimate your measly force of five frigates and will try to find you, but that is where your capital ship will come in... [e digicons]}
[/e] bwahaha!
I have found that if you launch repetitive short, fast attacks against your opponent's planets, he will play defensively for a while and slow his advancement long enough for you to reach RA level...[e digicons]:-"[/e] and terminate him for his mistakes! [e digicons]:cylon:[/e]