Yes brother Insha'Allah that is correct. I do the same myself whenever I can get my sinning self to pray Tahajjud. There was a fatwa on Islamweb which confirmed that you can recite multipe Surahs after Surah Fatiha in one rakat, as the Prophet has been reported to do it (can't find the fatwa right now). Similarly, some knowledgeable brothers at my local Masjid had told me the same and they said they had checked with more than one mufti on this. However, the talk of reciting Surahs in order without skipping never came up, and honestly I didn't think of it. The way it was said was that if one doesn't know any long Surahs then Insha'Allah they can just recite whichever shorter Surahs they know to make their rakats longer. I would say Insha'Allah the way you're saying (skipping between Surahs) is perfectly fine because if we knew all Surahs then we would be huffaz. one day. Insha'Allah the knowledgeable will correct me if I'm wrong. Allah knows best.