Raise an army of skeletal laborers. They’re cheap, tireless, work 24/7, and will go until you tell them to stop. Have them render the doors down into portable chunks (even bits as small as coins) and transport them overland to wherever you want them.
If skeletons aren’t your bag, golem works just as well.
Don’t forget your greatest resource - the abilities of your party members themselves.
All of your fighting-oriented classes have probably kitted themselves out with Belts of STR, and if they min-maxed properly can drag at least 2000lbs worth of stuff.
Do you have a summoner? Then they have an eidolon.
Do you have a druid? Then they can wildshape (further increasing their stats, and if they choose a quadruped form, have greater carrying capacities than bipeds) AND they have an animal companion.
Do you have a caster with Animate Dead? Instant skeleton and/or zombie army.
And then, don’t forget your utility spells. As mentioned, Ant Haul is very nice. Dimension Door doesn’t have an upper limit to the size of the object touched, and though it has a limited line of sight range, at 7/8 level that’ll still save quite a bit of travel. Teleport’s even greater if you have familiarity with where you’re headed. If you don’t care too much about retaining the shape of the doors, Fabricate them into smaller, easier to handle chunks.
There’s also magic items. Bags of Holding, Portable Doors, etc. etc. etc.
If you can’t take it with you right away, then you should totally secure it via mundane and magical traps. Then hope that some higher-level party doesn’t breeze through and use my above strategies to rob you blind.
Again, we’re talking about close to seventy tons of solid metal. It’s not your wallet, and you don’t need to worry about some pickpocket snatching it when you’re not looking.
Any plan that does not involve using weight-ignoring magic is just pointlessly making things harder for yourself.