You could use the Calendar function in Marketo to show all the planned email campaigns coming up and what the lists are. Or if you want to keep it in SFDC you can just add members to campaigns weeks/months prior to the send actually going out. Adding someone as a campaign member shouldn't harm the lead/contact record, it just shows they're part of upcoming campaigns in the campaigns calendar in SFDC.
Do you link your SFDC/Marketo campaigns together using the sync? If so, you could add them to the program in Marketo and it will automatically add them as a member in the SFDC campaign using a list, or smart campaign.
Hope this helps?