Could you post what Fr. Seraphim said? Perhaps it is quoted online already somewhere (e.g. orthodoxinfo)?
[Obligatory Disclaimer] We really shouldn't talk of "minimum" stuff in Orthodoxy, or just doing "enough." We should always want to do more, and it should be a joy! [/Disclaimer]
Now that that's out of the way. I'd say... morning and evening prayers, pre-communion prayers of some type, fasting when appointed, liturgy attendance regularly, participation in the sacraments as per the norm in your parish, a willingness to cultivate the virtues (humility, etc.) and engage in spiritual practices (almsgiving) to some extent or other, an attempt to lead a good Christian life (e.g. not being a jerk to people at work or school).