While Venus can support cloud city type colonies, what makes it hard is that you will have to bring them with you, or build them from asteroids along the way.

While Venus can support cloud city type colonies, what makes it hard is that you will have to bring them with you, or build them from asteroids along the way. Since Mars has an atmosphere, you can use it to get the delta-v costs to be in the ball-park of landing on the moon. If the numbers SpaceX posted for going to Mars are in the right ballpark, it looks like bypassing construction in orbit is the fastest way to backup humanity. Long term it might be more expensive to do it that way, but it would extend the timeline by decades. Another advantage of doing Mars first is that anyone wanting to do orbital construction will be able to sell their goods to colonists which need lower tech items than the advanced stuff like semiconductors you need for making satellites. This should help bootstrap the industry as making simple, heavy goods (eg: shovels) is easier than trying to make more complex items.