How do I ensure that I'm capturing all the video/audio data in the following process to copy and edit home movies?

I copied home movies from two analog camcorder tapes to a DVD+RW disk on a standalone Philips DVDR80 recorder/player using M1 (60 mins/disk) video mode. Each of the two tapes has somewhat less than 30 minutes video/audio on it. When I play the DVD+RW disk on the Philips DVDR80, there are two titles as expected -- one for each of the tapes recorded -- and the disk plays fine.

On my PC there is a Memorex dual format DVD-R/W+R/W recorder/player. Windows (XP Pro) Explorer shows the DVD+RW disk contains two folders: VIDEO_RM and VIDEO_TS (and no AUDIO_TS folder). (I understand from Philips that VIDEO_RM contains files for navigation on a standalone DVD recorder. The information I have is less clear regarding the VIDEO_TS folder.)

There are ten files in the VIDEO_TS folder as follows, with file size (KB) reported by Windows Explorer, and duration (min:sec) and "capacity" (MB) reported by TMPGEnc DVD Author 1.5 (* means the file is not listed by TMPGEnc as one that can be imported):

VIDEO_TS.BUP, 12 KB, *
VIDEO_TS.IFO, 12 KB, *
VIDEO_TS.VOB, 320 KB, *
VTS_01_0.BUP, 52 KB, *
VTS_01_0.IFO, 52 KB, *
VTS_01_1.VOB, 741,472 KB, 29min 54sec, 2079 MB
VTS_01_2.VOB, 741,472 KB, 22min 10sec, 1541 MB
VTS_01_3.VOB, 741,472 KB, *
VTS_01_4.VOB, 741,472 KB, 29min 54sec, 2079 MB
VTS_01_5.VOB, 741,560 KB, 22min 10sec, 1541 MB

(I understand the *.BUP are just backups of the *.IFO.) Total size of all the files (both folders) on the DVD+RW disk is about 3.53 GB. All the files above in VIDEO_TS have file date of 12/31/1999 7:00pm, even though they were not created on that date.

Questions:

(1) Why do the files have that file date if it's not accurate? (Just curious.)

(2) What is the VIDEO_TS.VOB file -- does it contain pointers to titles or chapters in other files?

(3) Why are there five VTS_01_x.VOB files?

(4) Why are their file sizes (nearly) the same but (except as noted below) the durations and capacities are not?

(5) Why does TMPGEnc recognize only some of the *.VOB files?

(6) What is the VTS_01_3.VOB file?

(7) Why are *1.VOB and *4.VOB shown as having the same capacity and duration (they also each seem to display the same video/audio when played in TMPGEnc and in Windows Media Player 9), and likewise for *2.VOB and *5.VOB (but why is *5.VOB slightly larger than *2.VOB in KB)?

(8) How is it possible that adding up the durations for the four files recognized by TMPGEnc comes to 104 minutes -- twice the length of video/audio I recorded and more than the 60 minutes capacity on the DVD+RW disk? And adding up the MB capacities as reported by TMPGEnc comes to more than 7 GB, larger than the DVD+RW disk. (Surely some of the *.VOB files are not copies/backups of other *.VOB files.)

(9) What is the relationship or correspondence among DVD+RW titles, chapters, *.IFO, and *.VOB files? (Is there a tutorial somewhere?) Apparently not a one-to-one relationship: there are only two titles, and the Philips DVDR80 records chapter marks every 5 minutes, so there are more chapters in the two titles than there are *.VOB files.

(10) My objective is to use TMPGEnc to import the video/audio from the DVD+RW disk, edit out unwanted scenes on the hard drive, and write back the edited video/audio to the DVD disk (a new DVD+RW or DVD+R disk or after erasing the original DVD+RW disk) -- as I understand it, no encoding or re-encoding is needed. Do I need to import and edit all four of the *.VOB files recognized by TMPGEnc (even though *1.VOB and *4.VOB seem to be redundant, as are *2.VOB and *5.VOB)? Will I be losing video/audio data if I don't?

(11) Could the utilities IfoEdit, VobEdit, and DVDDecrypter be helpful in getting to the bottom of this?

Hypothesis: Perhaps I'm misinterpreting the duration and capacity as reported by TMPGEnc, and in fact these are not associated just with individual VOB files. E.g., could it be that TMPGEnc (and Windows Media Player 9 as well) actually need all five VTS_01_x.VOB files to play the full video/audio of both titles, and, for example, that *1.VOB and *4.VOB both are needed to play/edit title 1, and TMPGEnc somehow (and WMP9) knows that? So although I tell TMPGEnc to import only *1.VOB (or only *.4.VOB) it actually knows somehow to import the data from both *1.VOB and *4.VOB? (Maybe there is a pointer from the end of *1.VOB to the start of *4.VOB? In which case, why have two files for one title? Is there a file size limit?)

As this is my first post, I apologize if these are basic questions or questions not otherwise appropriate for this forum. (I have gotten fairly ambiguous information from others, not on DVDRHelp, on these questions so my post intentionally is meant to be detailed and precise -- but I realize rather lengthy -- so as to avoid ambiguous questions or background information on my part). Thanks very much for any insights.