Can we take advantage of IRS Section 1031 and Section 121

[Christine B.]

My husband and I bought 30 acres in 1994 (undeveloped) for $119K and in 1999 we built a home on the property for $200K.  We have been approached to sell the property to a developer with 3 proposed scenarios:

1) sell 25 acres, we retain 5 acres and house - $1.2M

2) sell entire property - house will be demolished - $1.43M

3) Sell 25 acres to developer $1.2M,  sell house and 5 acres separately $400K

Option 3 provides for the greatest cash proceeds, however I'm trying to determine what the tax implications are of each scenario.  In which scenarios can we maximize the  IRS Section 1031 and Section 121.  

Scenario 1 - can only use 1031 like exchange - with limited cash retained (cost bases of the 25 acres) without paying capital gains

Scenario 2 & 3 - Can we utilize IRS Section 1031 and Section 121 for both scenarios.  And in scenario 3, do both sales have to take place at the same time? 

Any feedback is much appreciated. 

TIA.