Jesus said, "If I lay down my life I have power to take it up again." How could He do this without being in a spirit form coming at it from the otherside of this cosmos (which many refer to as the otherside of this veil?)
2 Corinthians 12
 It is not expedient for me doubtless to glory. I will come to visions and revelations of the Lord.  I knew a man in Christ above fourteen years ago, (whether in the body, I cannot tell; or whether out of the body, I cannot tell: God knoweth;) such an one caught up to the third heaven.  And I knew such a man, (whether in the body, or out of the body, I cannot tell: God knoweth;)  How that he was caught up into paradise, and heard unspeakable words, which it is not lawful for a man to utter.
Maybe Paul alludes to two different bodies, one's own individual body and being a member of the body of Christ. Whether or not one's own body is in view with both mentions, it seems He believes in experiencing things as if one had some resemblance to a soulical function outside the body. There are lists of Scripture in Watchman Nee's book The Spiritual Man that speak of the spirit functioning in just about any way the soul can function. Scripture knows there is a mind of the spirit and a fleshly or carnal mind.
1 Peter 317--46...
 For [it is] better, if the will of God be so, that ye suffer for well doing, than for evil doing.  For Christ also hath once suffered for sins, the just for the unjust, that he might bring us to God, being put to death in the flesh, but quickened by the Spirit:  By which also he went and preached unto the spirits in prison;  Which sometime were disobedient, when once the longsuffering of God waited in the days of Noah, while the ark was a preparing, wherein few, that is, eight souls were saved by water.  The like figure whereunto [even] baptism doth also now save us (not the putting away of the filth of the flesh, but the answer of a good conscience toward God,) by the resurrection of Jesus Christ:  Who is gone into heaven, and is on the right hand of God; angels and authorities and powers being made subject unto him. (1Pe 3:1-22 KJV)
 Forasmuch then as Christ hath suffered for us in the flesh, arm yourselves likewise with the same mind: for he that hath suffered in the flesh hath ceased from sin;  That he no longer should live the rest of [his] time in the flesh to the lusts of men, but to the will of God.  For the time past of [our] life may suffice us to have wrought the will of the Gentiles, when we walked in lasciviousness, lusts, excess of wine, revellings, banquetings, and abominable idolatries:  Wherein they think it strange that ye run not with [them] to the same excess of riot, speaking evil of [you]:  Who shall give account to him that is ready to judge the quick and the dead.  For for this cause was the gospel preached also to them that are dead, that they might be judged according to men in the flesh, but live according to God in the spirit.
In the 2nd chapter of Jonah he dies and goes to hell (sheol) for ever (according to the KJV, though it was only 3 days) and it is from there he remembered his vow. There he prayed. From there God heard and answered, making the big fish vomit him out onto dry land. I know someone who came to believe in the Salvation of all because of believing what is written in this one chapter.
Then there is the story of Lazarus. While it is just fine to understand it as a parable, that doesn't invalidate it as saying on a natural level whatever it says. Why should we think Jesus would mislead us by speaking of Abraham, Dives and Lazarus experiencing their environment, being conscious and carrying on a conversation with each other if this was impossible and a misrepresentation of the true state of affairs when we die?
As Solomon said there is no knowledge or praise in (is it sheol or the other Hebrew word meaning "the grave?") can be resolved by the fact the body (which also is you) has no such experience any more.
Demons, possibly in a lower dimension, seek to escape dryness (?) by dwelling in bodies again.
If we sleep here I don't know any definite reason why we wouldn't also sleep during certain intervals when out of the body until resurrection. Some think the spirit doesn't sleep; but that only seems intimated by certain Scriptures, not clearly said. It is written that the spirit can faint.
One opinion I think is true, whatever we are in a death state, it cannot be that it is just like being alive, being embodied. Why then would God not keep us there rather than go to all the trouble of bringing forth an incorruptible physical immortality? He calls it the expectation of all creation.
(I'm not looking up every reference for y'all at this time, OK?)_