To rack up Marriott pts, you only have 2 options:
1) transfer Chase UR pts to Marriott (don't do this, UR are much more valuable compared to Marriott pts)
2) the Chase Marriott card...I believe you can find a link for a 70k sign up bonus

Take some time to see what you can do with 70k Marriott pts. Add'ly Marriott typically runs promos where you can stay 2 times (paid stays) and get a free night at a category 4/5 Marriott. For your business trips it may be helpful to leverage that deal. You would also earn points for the paid stay which may help to add to your 70k Marriott pts balance (if you were to get the credit card). By combining your business trips/Marriott MegaBonus promos with signing up for the Chase Marriott credit card, you could easily wind up with 70k+ Marriott pts plus 2 free nights in a Cat 4/5 hotel. Plus, with the Marriott card, each year you keep the card (and pay the $85 annual fee), you get 1 free night in a Category 5 (it shouldn't be too hard to derive value from that...the room just needs to be >$85).

Even though transferring 30k Chase UR pts to 30k Marriott pts to redeem for a hotel night is a terrible idea, if you have 74k Marriott pts and need to have 80k Marriott pts for the redemption you'd like to have, then transferring 6k Chase UR pts to Marriott pts is not that bad a deal (this is one of the beauties of Chase's UR...the ability to "top off" your loyalty accounts in many different programs).