Does the target of Awaken need to be within range throughout the casting?

Question

After spending the casting time [8 hours] tracing magical pathways within a precious gemstone, you touch a huge or smaller beast or plant. The target must have either no Intelligence score... [etc]

After a PC spends 8 hours preparing an Awaken gemstone, must they touch a creature to use it on immediately?

1) Could a PC prepare the stone starting within touching range of the creature, allow the creature move away, and then touch the creature if it is within range 8 hours later?

2) Could a PC prepare the stone out of range of the creature and then cast the spell if the creature is within range 8 hours later?

I have seen some people online state that the caster must be touching the target for the entire duration, but that seems to be explicitly contradicted by the spell's text, which clearly states that "you touch [target]" "after" 8 hours.

The PHP states that spells with long casting times use up your actions, but it says nothing about not being able to move while casting the spell (it even seems to imply you can take bonus actions):

Certain spells (including spells cast as rituals) require more time to cast: minutes or even hours. When you cast a spell with a casting time longer than a single action or reaction, you must spend your action each turn casting the spell, and you must maintain your concentration while you do so.

I understand there might be a range issue here, but the PHB (p202 I think?) merely states:

The target of a spell must be within the spell's range. For a spell like magic missile, the target is a creature. For a spell like fireball, the target is the point in space where the ball of fire erupts.

It does not state when the target must be in range: when the spell is first cast? For the entire duration? There is an ambiguity here, and to me it seems that it is clearly filled by the text of Awaken, which says exactly when you must be within touching range: after spending 8 hours preparing the gem. From this point of view, it seems like option #1 above is possible: you could spend 8 hours preparing a gem while at any distance away from the target, approaching the target at leisure so long as you maintain concentration and don't take any actions. Even if range must be within touching on casting the spell, I can't find any text that says you must be within range for the entire duration.

Note that Simulacrum, another long-casting time spell that involves preparation of a physical item, is similarly clear about where the PC needs to be, how they can use their action economy, and the range of the effect. This implies that Awaken's apparent open endedness on this issue truly does mean that it allows for the circumstance I am proposing.

Simulacrum

You shape an illusory duplicate of one beast or humanoid that is within range for the entire casting time of the spell.

If the rules always required a target to be within range during the entire casting time, why did the writers of Simulcrum feel the need to explicitly state that the target in this case must be within range for the casting time? The fact that this needs to be stated implies that it is not always true: therefor, the fact that it's not stated in Awaken implies that a target does not need to be within range until it is touched.

I know this seems like more of a rant and less of a question, but that's really not so. Despite all of the above arguments, it seems as if Awaken simply can't work this way: otherwise, any Trex is just a good hiding spot, a dash action, and a touch away from becoming an easy month-long (or longer!) servant. Please tell me why the above arguments are wrong.

Answer 1

Range only matters at the time the spell is cast.

This answer might not fit the flavor of the spell but reflects the rules as written.

This is explicitly called out in the Sage Advice Compendium which states the following:

If you’re concentrating on a spell, do you need to maintain line of sight with the spell’s target or the spell’s effect?

You don’t need to be within line of sight or within range to maintain concentration on a spell, unless a spell’s description or other game feature says otherwise.

Since you are allowed to concentrate on any spell without its target being in range only to acquire the target later, such as by preparing to cast Firebolt on the first enemy you see, you should be able to do the same thing here.

In your case Awaken has a casting time of 8 hours and a range of Touch. This means that for the first 7 hours and 59 minutes which you spend concentrating on this spell, you do not have to be within touch range of your intended target, though you should still be "tracing magical pathways within a precious gemstone".

Once all 8 hours have elapsed you must then touch a creature or a plant to successfully cast the spell.

This means that the answer to your questions #1 and #2 is yes.