Lots of stuff to cover here, so I'll try to keep it short. Married with kids and currently financing our home. My wife and I both have auto loans, and I myself have student loans nearly equal to my mortgage (yuck!). My goal is to buy property (somewhere between 10-20 acres) and build a home for our family to move into as quickly and as safely as possible. We've been spenders in the past but have both agreed and committed to making this happen.
Current path: pay off car loans then student loans, save and acquire land then build. This will realistically take us 5-6 years.
Proposed idea: refinance home and pull out enough principal to pay off a car loan then continue with above plan. This puts us in the 4-5 year mark.
Additional thought: change traditionally mortgage to an interest only loan to be able to put more money towards car loan and student loans. Any other thoughts?
Basically we will not break ground on a new home until auto loans and my student loans are paid. I want to make that happen as fast as possible.

What is the term of your current mortgage?

How much equity do you have in your current home?

Do you mind sharing the current interest rates, payoff dates and approximate balances of your outstanding debts?

Could you refinance any of the debt for better rates? I cut a full percent off my student loan by refinancing to Sofi.

Do you have any credit card debt? Do you pay the credit cards off monthly?

What is your retirement savings like?

Do you have a true 6 month emergency savings fund?

Have you looked at land values in your area of interest? Acreage can run anywhere from $1,000 to $10,000+.

Have you considered cutting back on monthly expenses? Cut out coffee at Starbucks, cut down on the Internet speed, reduce the number of cable channels (or cancel it completely and get an over-the-air antenna), cut back on cell phone data plans, shop car/home insurance plans and review and adjust your limits/deductibles, bag lunch instead of eating out, etc.

I would strongly advise you to not do an interest-only mortgage. I recommend paying off the highest interest loan first in most cases. Some people may prefer to pay off the smallest balance first because that feels like more progress. Do whichever will keep you motivated to stick to your plan.

At least in my state, I can buy less than 10 acres with 15% down.  10+ acres requires 25% down.

You'd need to front the cash for the downpayment on the construction loan, and that's a wild card.  You present the land and your blueprints, and someone appraises, and you have to have 20% down to start construction.  How much equity do you have in the home?

My mortgage guy said bluntly, "If you want to build with a construction loan, you need to be starting with a pile of cash."

We've been talking with banks about construction loans lately.  Mind you we're doing so as a construction company and  rental company and not for a personal residence.  Find a good local bank and talk with a loan officer and they will tell where you will need to be financially when you go to get the loan.  

Most will loan 75% of appraisal value if you own the land with some only loaning 60%.  The 60% bank will loan that for personal as well.

Let me get this straight, you have a mortgage, auto loans, students loans and youre asking about buying a second home!!??

I don't mean to be rude but you shouldn't even be discussing buying a second home until you are debt free. It doesn't matter how many times you refinance, what rate you get or what method of debt consolidation you use, its still debt and it sounds to me like you are up to your eye balls in it.

Have you ever sat down and calculated how much youre paying a year in interest? I was like you once with a mortgage, car loans and student loads, I was paying over $10,000 a year in interest! Most people will pay more in interest on their mortgage than their home is worth if you take the full 30 years to pay it off.

IMO I would move the second home down a few on the priority list and get focused on being debt free, then save up a large down payment or even the whole purchase price of the second home in cash.

Also, check out Dave Ramsey, he offers a program with great financial advice. The program completely changed the way I handle money, its been blessing. In just a few years my wife and I went from hopelessly in debt. to becoming debt free and now we are making plans for an early retirement.